diff --git a/apps/backend/scripts/backfill-internal-sku-mappings.ts b/apps/backend/scripts/backfill-internal-sku-mappings.ts
new file mode 100644
index 00000000..044a6ed2
--- /dev/null
+++ b/apps/backend/scripts/backfill-internal-sku-mappings.ts
@@ -0,0 +1,84 @@
+/**
+ * 从 PDD 纯数字内部 SKU 的订单项回填中文映射（只读扫描 + 幂等写入）。
+ *
+ * 只处理 sku_name 含中文、sku_code 为纯数字的情况；
+ * 找不到中文名的纯数字码会列出来，等运营补映射。
+ *
+ * 用法：npx tsx scripts/backfill-internal-sku-mappings.ts [--apply]
+ */
+import { closeDb, query } from '../src/db/client.js'
+import { upsertInternalSkuMapping } from '../src/services/fulfillment/internal-sku-mapping-service.js'
+
+async function main() {
+  const apply = process.argv.includes('--apply')
+  const rows = await query<{
+    provider: string
+    shop_id: string
+    sku_code: string
+    sku_name: string
+    total: number
+  }>(
+    `
+      SELECT o.provider, o.shop_id, oi.sku_code, MIN(oi.sku_name) AS sku_name, count(*)::int AS total
+      FROM order_items oi
+      JOIN orders o ON o.id = oi.order_id
+      WHERE btrim(COALESCE(oi.manual_sku_key, '')) ~ '^[0-9]+$'
+        AND btrim(COALESCE(oi.sku_name, '')) ~ '[一-龥]'
+      GROUP BY 1, 2, 3
+      ORDER BY 5 DESC
+    `,
+  )
+  const unresolved = await query<{
+    provider: string
+    shop_id: string
+    sku_code: string
+    total: number
+  }>(
+    `
+      SELECT o.provider, o.shop_id, oi.sku_code, count(*)::int AS total
+      FROM order_items oi
+      JOIN orders o ON o.id = oi.order_id
+      WHERE btrim(COALESCE(oi.manual_sku_key, '')) ~ '^[0-9]+$'
+        AND btrim(COALESCE(oi.sku_name, '')) !~ '[一-龥]'
+      GROUP BY 1, 2, 3
+      ORDER BY 4 DESC
+    `,
+  )
+
+  let written = 0
+  for (const row of rows.rows) {
+    if (apply) {
+      await upsertInternalSkuMapping({
+        provider: row.provider,
+        shopId: row.shop_id,
+        matchType: 'sku_code',
+        matchValue: row.sku_code,
+        internalSku: row.sku_name,
+        priority: 100,
+        source: 'backfill',
+        note: `从 ${row.total} 条订单项回填`,
+      })
+    }
+    written += 1
+  }
+
+  console.log(
+    JSON.stringify(
+      {
+        apply,
+        canBackfill: rows.rows.length,
+        backfilled: written,
+        unresolved: unresolved.rows,
+      },
+      null,
+      2,
+    ),
+  )
+}
+
+main()
+  .catch((error) => {
+    console.error(error)
+    process.exitCode = 1
+  })
+  .finally(() => closeDb())
diff --git a/apps/backend/src/db/migrations/117_internal_sku_mappings.sql b/apps/backend/src/db/migrations/117_internal_sku_mappings.sql
new file mode 100644
index 00000000..7f241f0c
--- /dev/null
+++ b/apps/backend/src/db/migrations/117_internal_sku_mappings.sql
@@ -0,0 +1,30 @@
+-- 117_internal_sku_mappings.sql
+--
+-- 平台字段 → 内部中文 SKU 的补全映射。
+-- manual_sku_key 生成列优先取 skuNick/outSkuSn/sku_code/sku_name；
+-- 当平台只给纯数字码、没有中文 skuNick/outSkuSn 时，用本表补成内部中文 SKU。
+
+CREATE TABLE IF NOT EXISTS internal_sku_mappings (
+  id BIGSERIAL PRIMARY KEY,
+  provider TEXT NOT NULL DEFAULT '',
+  shop_id TEXT NOT NULL DEFAULT '',
+  match_type TEXT NOT NULL CHECK (match_type IN ('sku_code', 'sku_nick', 'out_sku_sn', 'spec', 'sku_name')),
+  match_value TEXT NOT NULL,
+  internal_sku TEXT NOT NULL,
+  priority INTEGER NOT NULL DEFAULT 100,
+  enabled BOOLEAN NOT NULL DEFAULT TRUE,
+  source TEXT NOT NULL DEFAULT 'manual',
+  note TEXT NOT NULL DEFAULT '',
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS uq_internal_sku_mappings_key
+  ON internal_sku_mappings (provider, shop_id, match_type, match_value);
+
+CREATE INDEX IF NOT EXISTS idx_internal_sku_mappings_internal
+  ON internal_sku_mappings (internal_sku)
+  WHERE enabled = TRUE;
+
+COMMENT ON TABLE internal_sku_mappings IS
+  '平台字段 → 内部中文 SKU 映射；provider/shop_id 为空表示全局，priority 越小越优先';
diff --git a/apps/backend/src/services/fulfillment/internal-sku-mapping-service.ts b/apps/backend/src/services/fulfillment/internal-sku-mapping-service.ts
new file mode 100644
index 00000000..abc9a07e
--- /dev/null
+++ b/apps/backend/src/services/fulfillment/internal-sku-mapping-service.ts
@@ -0,0 +1,115 @@
+import { query } from '../../db/client.js'
+
+export type InternalSkuMappingMatchType =
+  | 'sku_code'
+  | 'sku_nick'
+  | 'out_sku_sn'
+  | 'spec'
+  | 'sku_name'
+
+export type InternalSkuMappingCandidate = {
+  matchType: InternalSkuMappingMatchType
+  value: unknown
+}
+
+export type ResolvedInternalSkuMapping = {
+  id: number
+  internalSku: string
+  source: string
+}
+
+export function normalizeInternalSkuMappingValue(value: unknown): string {
+  return String(value ?? '')
+    .replace(/\s+/g, '')
+    .trim()
+}
+
+/**
+ * 按平台字段候选值查内部中文 SKU 映射。
+ *
+ * 优先级：精确 provider/shop > 全局；同范围按 priority 升序、id 升序。
+ * 返回 null 表示没有映射，调用方回退 manual_sku_key 生成列。
+ */
+export async function resolveInternalSkuMapping(input: {
+  provider?: string | null
+  shopId?: string | null
+  candidates: InternalSkuMappingCandidate[]
+}): Promise<ResolvedInternalSkuMapping | null> {
+  const provider = String(input.provider || '').trim()
+  const shopId = String(input.shopId || '').trim()
+  const pairs = input.candidates
+    .map((candidate) => ({
+      matchType: candidate.matchType,
+      matchValue: normalizeInternalSkuMappingValue(candidate.value),
+    }))
+    .filter((candidate) => candidate.matchValue !== '')
+  if (pairs.length === 0) return null
+
+  const result = await query<{ id: number; internal_sku: string; source: string }>(
+    `
+      SELECT m.id, m.internal_sku, m.source
+      FROM internal_sku_mappings m
+      JOIN unnest($3::text[], $4::text[]) AS c(match_type, match_value)
+        ON m.match_type = c.match_type AND m.match_value = c.match_value
+      WHERE m.enabled = TRUE
+        AND (m.provider = '' OR m.provider = $1)
+        AND (m.shop_id = '' OR m.shop_id = $2)
+      ORDER BY
+        CASE WHEN m.provider = $1 AND m.shop_id = $2 THEN 0
+             WHEN m.provider = $1 THEN 1
+             WHEN m.shop_id = $2 THEN 2
+             ELSE 3 END,
+        m.priority ASC,
+        m.id ASC
+      LIMIT 1
+    `,
+    [provider, shopId, pairs.map((pair) => pair.matchType), pairs.map((pair) => pair.matchValue)],
+  )
+  const row = result.rows[0]
+  if (!row) return null
+  return {
+    id: Number(row.id),
+    internalSku: String(row.internal_sku || '').trim(),
+    source: String(row.source || 'manual'),
+  }
+}
+
+export async function upsertInternalSkuMapping(input: {
+  provider?: string | null
+  shopId?: string | null
+  matchType: InternalSkuMappingMatchType
+  matchValue: string
+  internalSku: string
+  priority?: number
+  source?: string
+  note?: string
+}): Promise<number> {
+  const result = await query<{ id: number }>(
+    `
+      INSERT INTO internal_sku_mappings (
+        provider, shop_id, match_type, match_value, internal_sku,
+        priority, enabled, source, note, created_at, updated_at
+      ) VALUES ($1, $2, $3, $4, $5, $6, TRUE, $7, $8, NOW(), NOW())
+      ON CONFLICT (provider, shop_id, match_type, match_value)
+      DO UPDATE SET
+        internal_sku = EXCLUDED.internal_sku,
+        priority = EXCLUDED.priority,
+        enabled = TRUE,
+        source = EXCLUDED.source,
+        note = EXCLUDED.note,
+        updated_at = NOW()
+      RETURNING id
+    `,
+    [
+      String(input.provider || '').trim(),
+      String(input.shopId || '').trim(),
+      input.matchType,
+      normalizeInternalSkuMappingValue(input.matchValue),
+      String(input.internalSku || '').trim(),
+      Number.isFinite(Number(input.priority)) ? Number(input.priority) : 100,
+      String(input.source || 'manual').trim() || 'manual',
+      String(input.note || '').trim(),
+    ],
+  )
+  return Number(result.rows[0]?.id || 0)
+}