diff --git a/backend/internal/database/migrations/005_seed_product_catalog.sql b/backend/internal/database/migrations/005_seed_product_catalog.sql
new file mode 100644
index 0000000..57719a8
--- /dev/null
+++ b/backend/internal/database/migrations/005_seed_product_catalog.sql
@@ -0,0 +1,81 @@
+-- 默认商品目录种子数据：为自营商户预置和平精英商品，成本单位为积分。
+-- cost_amount = 消耗积分；price_amount = 价钱(元) * 10 = 售价积分。
+
+-- 1. 插入平台商品目录（幂等）
+INSERT INTO products (code, name, category, status)
+SELECT v.code, v.name, v.category, 'active'
+FROM (VALUES
+  ('suit_alan_walker',      '套装-Alan Walker',         '套装'),
+  ('suit_shadow_gothic',    '套装-暗影哥特',            '套装'),
+  ('top_black_elite_trainer','黑色高级特训官上衣',       '上衣'),
+  ('m416_hamster_gray',     'M416-仓鼠灰灰',            '枪械'),
+  ('bag_cute_bear',         '萌熊伴侣背包',             '背包'),
+  ('suit_dual_fluffy',      '套装-双彩绵绵',            '套装'),
+  ('suit_pink_sheep',       '套装-糯粉咩咩',            '套装'),
+  ('suit_first_peach',      '套装-恋恋初桃',            '套装'),
+  ('suit_romantic_destiny', '套装-浪漫天命',            '套装'),
+  ('pack_western_cowboy',   '西部牛仔大礼包',           '礼包'),
+  ('smoke_pink_sheep',      '烟雾弹-糯粉咩咩',          '投掷物'),
+  ('frag_pink_sheep',       '破片手榴弹-糯粉咩咩',      '投掷物'),
+  ('suit_hamster_gray',     '套装-仓鼠灰灰',            '套装'),
+  ('suit_cute_bear',        '套装-萌熊伴侣',            '套装'),
+  ('bag_pink_sheep',        '糯粉咩咩背包',             '背包'),
+  ('helmet_pink_sheep',     '糯粉咩咩头盔',             '头盔'),
+  ('bag_hamster_gray',      '仓鼠灰灰背包',             '背包'),
+  ('helmet_hamster_gray',   '仓鼠灰灰头盔',             '头盔'),
+  ('suit_western_mystery',  '套装-西部谜踪',            '套装'),
+  ('helmet_panda_treasure', '国宝胖达头盔',             '头盔'),
+  ('suit_panda_round',      '套装-胖达圆圆',            '套装'),
+  ('suit_panda_tuan',       '套装-胖达团团',            '套装'),
+  ('pack_lava_ranger',      '熔岩游骑兵礼包',           '礼包'),
+  ('suit_sand_dancer',      '套装-狂沙舞者',            '套装'),
+  ('pack_star_roam_outfit', '星际漫游服装礼包',         '礼包'),
+  ('pack_star_roam_weapon', '星际漫游枪械礼包',         '礼包'),
+  ('suit_cloud_bear',       '套装-绵云熊熊',            '套装')
+) AS v(code, name, category)
+ON CONFLICT (code) DO NOTHING;
+
+-- 2. 为自营商户创建可售商品（幂等，按 merchant_id + sku 唯一索引）
+INSERT INTO merchant_products (merchant_id, product_id, sku, display_name, price_amount, cost_amount, currency, stock, status)
+SELECT
+  m.id,
+  p.id,
+  p.code,
+  p.name,
+  v.price_amount,
+  v.cost_amount,
+  'POINT',
+  -1,
+  'active'
+FROM (VALUES
+  ('suit_alan_walker',      360,  360),
+  ('suit_shadow_gothic',    888,  888),
+  ('top_black_elite_trainer',360,  360),
+  ('m416_hamster_gray',     1680, 1680),
+  ('bag_cute_bear',         2880, 2880),
+  ('suit_dual_fluffy',      1124, 1124),
+  ('suit_pink_sheep',       1880, 1880),
+  ('suit_first_peach',      988,  988),
+  ('suit_romantic_destiny', 360,  360),
+  ('pack_western_cowboy',   3200, 3200),
+  ('smoke_pink_sheep',      488,  488),
+  ('frag_pink_sheep',       488,  488),
+  ('suit_hamster_gray',     1280, 1280),
+  ('suit_cute_bear',        1680, 1680),
+  ('bag_pink_sheep',        1680, 1680),
+  ('helmet_pink_sheep',     1680, 1680),
+  ('bag_hamster_gray',      1680, 1680),
+  ('helmet_hamster_gray',   1680, 1680),
+  ('suit_western_mystery',  1150, 1150),
+  ('helmet_panda_treasure', 2340, 2340),
+  ('suit_panda_round',      2340, 2340),
+  ('suit_panda_tuan',       2340, 2340),
+  ('pack_lava_ranger',      960,  960),
+  ('suit_sand_dancer',      840,  840),
+  ('pack_star_roam_outfit', 8360, 8360),
+  ('pack_star_roam_weapon', 5160, 5160),
+  ('suit_cloud_bear',       1348, 1348)
+) AS v(sku, price_amount, cost_amount)
+JOIN products p ON p.code = v.sku
+JOIN merchants m ON m.code = 'self-operated'
+ON CONFLICT (merchant_id, sku) DO NOTHING;