diff --git a/apps/backend/src/repositories/order-item-repo.ts b/apps/backend/src/repositories/order-item-repo.ts
index 3834fab1..2fa902a7 100644
--- a/apps/backend/src/repositories/order-item-repo.ts
+++ b/apps/backend/src/repositories/order-item-repo.ts
@@ -3,6 +3,7 @@ import type { PoolClient, QueryResult } from 'pg'
 import { query, withTransaction } from '../db/client.js'
 import type { OrderItemReplaceInput } from '../types/repository/inputs.js'
 import type { OrderItemRow } from '../types/repository/rows.js'
+import { safeJsonStringify } from '../utils/json.js'
 
 export type QueryExecutor = (text: string, params?: unknown[]) => Promise<QueryResult<any>>
 
@@ -71,8 +72,8 @@ export async function replaceOrderItemsWithExecutor(
         update.item.skuCode,
         update.item.skuName,
         update.item.quantity,
-        update.item.specJson || '{}',
-        update.item.itemSnapshotJson || update.item.specJson || '{}',
+        safeJsonStringify(update.item.specJson || '{}'),
+        safeJsonStringify(update.item.itemSnapshotJson || update.item.specJson || '{}'),
         update.item.updatedAt,
         update.orderItemId,
       ],
@@ -98,8 +99,8 @@ export async function replaceOrderItemsWithExecutor(
         create.skuCode,
         create.skuName,
         create.quantity,
-        create.specJson || '{}',
-        create.itemSnapshotJson || create.specJson || '{}',
+        safeJsonStringify(create.specJson || '{}'),
+        safeJsonStringify(create.itemSnapshotJson || create.specJson || '{}'),
         create.createdAt,
         create.updatedAt,
       ],
diff --git a/apps/backend/src/repositories/order-repo.ts b/apps/backend/src/repositories/order-repo.ts
index f6976f07..3a8b5de9 100644
--- a/apps/backend/src/repositories/order-repo.ts
+++ b/apps/backend/src/repositories/order-repo.ts
@@ -8,6 +8,7 @@ import type {
 } from '../types/repository/inputs.js'
 import type { OrderListQueryResult, OrderListRow, OrderRow } from '../types/repository/rows.js'
 import { isPlatformOrderIdLookupKeyword } from '../utils/platform-order-id.js'
+import { safeJsonStringify, sanitizeWellFormedUnicode } from '../utils/json.js'
 
 export type OrderQueryExecutor = <T extends QueryResultRow = QueryResultRow>(
   text: string,
@@ -147,12 +148,12 @@ export async function createOrderWithExecutor(
       input.platformOrderId,
       input.orderStatus,
       input.payStatus,
-      input.buyerId,
-      input.buyerName,
-      input.receiverContact,
+      sanitizeWellFormedUnicode(input.buyerId),
+      sanitizeWellFormedUnicode(input.buyerName),
+      sanitizeWellFormedUnicode(input.receiverContact),
       input.totalAmount,
       input.currency,
-      input.rawPayloadJson || '{}',
+      safeJsonStringify(input.rawPayloadJson || '{}'),
       input.paidAt || null,
       input.createdAt,
       input.updatedAt,
@@ -202,12 +203,12 @@ export async function updateOrderWithExecutor(
       input.shopName,
       input.orderStatus,
       input.payStatus,
-      input.buyerId,
-      input.buyerName,
-      input.receiverContact,
+      sanitizeWellFormedUnicode(input.buyerId),
+      sanitizeWellFormedUnicode(input.buyerName),
+      sanitizeWellFormedUnicode(input.receiverContact),
       input.totalAmount,
       input.currency,
-      input.rawPayloadJson || '{}',
+      safeJsonStringify(input.rawPayloadJson || '{}'),
       input.paidAt || null,
       input.updatedAt,
       Number(orderId),
diff --git a/apps/backend/src/services/order/order-service.ts b/apps/backend/src/services/order/order-service.ts
index 376ce79a..1c30dc9c 100644
--- a/apps/backend/src/services/order/order-service.ts
+++ b/apps/backend/src/services/order/order-service.ts
@@ -19,6 +19,7 @@ import {
 import { nowIso } from '../../utils/time.js'
 import { logDebug, logInfo, logIntegration, logWarn } from '../../utils/logger.js'
 import { createHttpError } from '../../utils/http.js'
+import { safeJsonStringify, sanitizeWellFormedUnicode } from '../../utils/json.js'
 import type { OrderItemRow, OrderRow, TaskRow } from '../../types/repository/rows.js'
 
 type SourceOrderItem = {
@@ -138,12 +139,12 @@ export async function upsertOrderFromSource(
       platformOrderId: event.platformOrderId,
       orderStatus: event.orderStatus,
       payStatus: event.payStatus,
-      buyerId: event.buyerId,
-      buyerName: event.buyerName,
-      receiverContact: event.receiverContact,
+      buyerId: sanitizeWellFormedUnicode(event.buyerId),
+      buyerName: sanitizeWellFormedUnicode(event.buyerName),
+      receiverContact: sanitizeWellFormedUnicode(event.receiverContact),
       totalAmount: event.totalAmount,
       currency: event.currency,
-      rawPayloadJson: JSON.stringify(event.rawPayload),
+      rawPayloadJson: safeJsonStringify(event.rawPayload),
       ...(event.paidAt !== undefined ? { paidAt: event.paidAt } : {}),
     }
     const mergedPayload = mergeSourceOrderState(existing, basePayload)
@@ -172,11 +173,11 @@ export async function upsertOrderFromSource(
       executor,
       order.id,
       resolvedFulfillmentItems.map((item) => ({
-        skuCode: item.skuCode,
-        skuName: item.skuName,
+        skuCode: sanitizeWellFormedUnicode(item.skuCode),
+        skuName: sanitizeWellFormedUnicode(item.skuName),
         quantity: item.quantity,
-        specJson: JSON.stringify(item.spec || {}),
-        itemSnapshotJson: JSON.stringify(item.snapshot || item.spec || {}),
+        specJson: safeJsonStringify(item.spec || {}),
+        itemSnapshotJson: safeJsonStringify(item.snapshot || item.spec || {}),
         createdAt: now,
         updatedAt: now,
       })),
diff --git a/apps/backend/src/services/platforms/pdd/pdd-order-mapper.test.ts b/apps/backend/src/services/platforms/pdd/pdd-order-mapper.test.ts
index be2a510a..3e391ad7 100644
--- a/apps/backend/src/services/platforms/pdd/pdd-order-mapper.test.ts
+++ b/apps/backend/src/services/platforms/pdd/pdd-order-mapper.test.ts
@@ -100,6 +100,33 @@ test('mapPddOrderToSourceEvent prioritizes out_sku_sn as primary matching field'
   assert.equal((item.spec as Record<string, unknown>).spec, '暗潮1钻')
 })
 
+test('mapPddOrderToSourceEvent sanitizes lone unicode surrogates and null bytes in buyer nickname/memo', () => {
+  const pddOrderWithSurrogates: PddRawOrderItem = {
+    order_sn: '260919-616772441623292',
+    order_status: 2,
+    order_status_str: '已发货',
+    order_amount: 10000,
+    goods_id: 888,
+    goods_name: '测试商品',
+    nickname: '\ud835*VIP\ud83c', // Unpaired lone surrogates
+    buyer_memo: '游戏ID: 12345\0null', // Null byte
+  }
+
+  const event = mapPddOrderToSourceEvent(pddOrderWithSurrogates, {
+    shopId: 'xiangrikui',
+    shopName: '向日葵网络游戏专营店',
+  })
+
+  assert.equal(event.buyerName, '\uFFFD*VIP\uFFFD')
+  assert.equal(event.buyerId, '\uFFFD*VIP\uFFFD')
+  assert.equal(event.receiverContact, '游戏ID: 12345null')
+
+  // JSON stringification should be 100% valid without lone surrogates or null bytes
+  const serialized = JSON.stringify(event.rawPayload)
+  assert.ok(!serialized.includes('\0'))
+  assert.doesNotThrow(() => JSON.parse(serialized))
+})
+
 test('mapPddOrderToSourceEvent reads nested order_goods when top-level goods fields missing', () => {
   const nestedOnly: PddRawOrderItem = {
     order_sn: '260915-111',
diff --git a/apps/backend/src/services/platforms/pdd/pdd-order-mapper.ts b/apps/backend/src/services/platforms/pdd/pdd-order-mapper.ts
index 45aaa6aa..571984b1 100644
--- a/apps/backend/src/services/platforms/pdd/pdd-order-mapper.ts
+++ b/apps/backend/src/services/platforms/pdd/pdd-order-mapper.ts
@@ -5,6 +5,7 @@
 
 import type { SourceOrderEvent } from '../../order/order-service.js'
 import type { JsonObject } from '../../../types/json.js'
+import { deepSanitizeUnicode, sanitizeWellFormedUnicode } from '../../../utils/json.js'
 
 export interface PddRawOrderItem {
   order_sn: string
@@ -180,9 +181,13 @@ export function mapPddOrderToSourceEvent(
   const externalSkuCode = skuCode
   const externalSkuName = skuName
 
+  const cleanRawOrder = deepSanitizeUnicode(rawOrder)
+  const cleanNickname = sanitizeWellFormedUnicode(rawOrder.nickname || '')
+  const cleanBuyerMemo = sanitizeWellFormedUnicode(rawOrder.buyer_memo || '').trim()
+
   // Retain the entire raw snapshot dictionary as requested / 保留原始报文完整快照
   const itemSnapshot: JsonObject = {
-    ...(rawOrder as unknown as JsonObject),
+    ...(cleanRawOrder as unknown as JsonObject),
     goodsId: goodsIdStr,
     goodsName,
     spec,
@@ -191,9 +196,9 @@ export function mapPddOrderToSourceEvent(
     quantity,
     orderAmount: Number(rawOrder.order_amount || 0),
     goodsAmount: Number(rawOrder.goods_amount || 0),
-    buyerMemo: String(rawOrder.buyer_memo || ''),
-    mallRemark: String(rawOrder.mall_remark || ''),
-    nickname: String(rawOrder.nickname || ''),
+    buyerMemo: cleanBuyerMemo,
+    mallRemark: sanitizeWellFormedUnicode(rawOrder.mall_remark || ''),
+    nickname: cleanNickname,
     orderTime: rawOrder.order_time,
     confirmTime: rawOrder.confirm_time,
   }
@@ -206,14 +211,14 @@ export function mapPddOrderToSourceEvent(
     platformOrderId: orderSn,
     orderStatus,
     payStatus,
-    buyerId: String(rawOrder.nickname || ''),
-    buyerName: String(rawOrder.nickname || ''),
+    buyerId: cleanNickname,
+    buyerName: cleanNickname,
     // Receiver contact is often buyer's recharge game ID / 买家留言通常为充值游戏账号
-    receiverContact: String(rawOrder.buyer_memo || '').trim(),
+    receiverContact: cleanBuyerMemo,
     totalAmount: Number(rawOrder.order_amount || 0),
     currency: 'CNY',
     paidAt,
-    rawPayload: rawOrder,
+    rawPayload: cleanRawOrder,
     items: [
       {
         itemId: goodsIdStr,
diff --git a/apps/backend/src/utils/json.test.ts b/apps/backend/src/utils/json.test.ts
new file mode 100644
index 00000000..e05837b6
--- /dev/null
+++ b/apps/backend/src/utils/json.test.ts
@@ -0,0 +1,55 @@
+import { test } from 'node:test'
+import assert from 'node:assert/strict'
+import {
+  parseJsonObject,
+  sanitizeWellFormedUnicode,
+  deepSanitizeUnicode,
+  safeJsonStringify,
+} from './json.js'
+
+test('sanitizeWellFormedUnicode handles null bytes and lone surrogates', () => {
+  // Null byte
+  assert.equal(sanitizeWellFormedUnicode('hello\0world'), 'helloworld')
+
+  // Lone high surrogate \ud835
+  const loneSurrogate = 'nickname\ud835test'
+  const cleaned = sanitizeWellFormedUnicode(loneSurrogate)
+  assert.equal(cleaned, 'nickname\uFFFDtest')
+
+  // Valid emoji surrogate pair \uD83D\uDE00 (😀) should remain intact
+  const validEmoji = 'Hello 😀'
+  assert.equal(sanitizeWellFormedUnicode(validEmoji), 'Hello 😀')
+})
+
+test('deepSanitizeUnicode recursively cleans objects and arrays', () => {
+  const input = {
+    user: 'buyer\ud83c',
+    nested: {
+      comment: 'good\0deal',
+      tags: ['cool\ud835', 'ok'],
+    },
+  }
+
+  const output = deepSanitizeUnicode(input)
+  assert.deepEqual(output, {
+    user: 'buyer\uFFFD',
+    nested: {
+      comment: 'gooddeal',
+      tags: ['cool\uFFFD', 'ok'],
+    },
+  })
+})
+
+test('safeJsonStringify produces valid JSON safe for postgres jsonb', () => {
+  const input = {
+    orderSn: '260919-123456',
+    nickname: '\ud835\ud83c*buyer',
+    nullByte: 'abc\0def',
+  }
+
+  const json = safeJsonStringify(input)
+  assert.ok(typeof json === 'string')
+  const parsed = JSON.parse(json)
+  assert.equal(parsed.nickname, '\uFFFD\uFFFD*buyer')
+  assert.equal(parsed.nullByte, 'abcdef')
+})
diff --git a/apps/backend/src/utils/json.ts b/apps/backend/src/utils/json.ts
index 4738ca5d..030a0707 100644
--- a/apps/backend/src/utils/json.ts
+++ b/apps/backend/src/utils/json.ts
@@ -64,6 +64,66 @@ function shouldPreserveIntegerToken(rawDigits: unknown): boolean {
   return unsigned > '9007199254740991'
 }
 
+export function sanitizeWellFormedUnicode(value: unknown): string {
+  if (value === null || value === undefined) return ''
+  const str = String(value)
+  if (!str) return ''
+  // 1. Remove null bytes (\u0000) which PostgreSQL text/jsonb columns strictly forbid
+  const withoutNull = str.replace(/\0/g, '')
+  // 2. Convert lone surrogates into replacement character U+FFFD
+  const toWellFormedFn = (withoutNull as { toWellFormed?: () => string }).toWellFormed
+  return typeof toWellFormedFn === 'function'
+    ? toWellFormedFn.call(withoutNull)
+    : withoutNull.replace(
+        /[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]/g,
+        '\uFFFD',
+      )
+}
+
+export function deepSanitizeUnicode<T>(value: T): T {
+  if (value === null || value === undefined) {
+    return value
+  }
+  if (typeof value === 'string') {
+    return sanitizeWellFormedUnicode(value) as unknown as T
+  }
+  if (Array.isArray(value)) {
+    return value.map((item) => deepSanitizeUnicode(item)) as unknown as T
+  }
+  if (isPlainObject(value)) {
+    const res: Record<string, unknown> = {}
+    for (const [k, v] of Object.entries(value)) {
+      const cleanKey = sanitizeWellFormedUnicode(k)
+      res[cleanKey] = deepSanitizeUnicode(v)
+    }
+    return res as unknown as T
+  }
+  return value
+}
+
+export function safeJsonStringify(value: unknown, fallback = '{}'): string {
+  if (value === undefined || value === null) {
+    return fallback
+  }
+  if (typeof value === 'string') {
+    const trimmed = value.trim()
+    if (!trimmed) return fallback
+    try {
+      const parsed = JSON.parse(trimmed)
+      const sanitized = deepSanitizeUnicode(parsed)
+      return JSON.stringify(sanitized)
+    } catch {
+      return JSON.stringify(sanitizeWellFormedUnicode(value))
+    }
+  }
+  try {
+    const sanitized = deepSanitizeUnicode(value)
+    return JSON.stringify(sanitized)
+  } catch {
+    return fallback
+  }
+}
+
 function isPlainObject(value: unknown): value is JsonObject {
   return Object.prototype.toString.call(value) === '[object Object]'
 }