diff --git a/backend/services/mining-admin-service/prisma/migrations/0001_init/migration.sql b/backend/services/mining-admin-service/prisma/migrations/0001_init/migration.sql
index 2831bd91..bd6a5060 100644
--- a/backend/services/mining-admin-service/prisma/migrations/0001_init/migration.sql
+++ b/backend/services/mining-admin-service/prisma/migrations/0001_init/migration.sql
@@ -689,8 +689,9 @@ CREATE UNIQUE INDEX "synced_daily_mining_stats_statDate_key" ON "synced_daily_mi
 CREATE UNIQUE INDEX "synced_day_klines_klineDate_key" ON "synced_day_klines"("klineDate");
 
 -- CreateIndex: synced_system_contributions
--- 使用 accountType + region_code 复合唯一键
-CREATE UNIQUE INDEX "synced_system_contributions_accountType_region_code_key" ON "synced_system_contributions"("accountType", "region_code");
+-- 使用 accountType + COALESCE(region_code, '__NULL__') 复合唯一键
+-- 注意：PostgreSQL 中 NULL != NULL，所以直接用 region_code 做唯一索引无法阻止重复的 (OPERATION, NULL)
+CREATE UNIQUE INDEX "synced_system_contributions_accountType_region_code_key" ON "synced_system_contributions"("accountType", COALESCE(region_code, '__NULL__'));
 CREATE INDEX "synced_system_contributions_accountType_idx" ON "synced_system_contributions"("accountType");
 CREATE INDEX "synced_system_contributions_region_code_idx" ON "synced_system_contributions"("region_code");
 
diff --git a/backend/services/mining-admin-service/src/infrastructure/kafka/cdc-sync.service.ts b/backend/services/mining-admin-service/src/infrastructure/kafka/cdc-sync.service.ts
index 97115630..a1a56a09 100644
--- a/backend/services/mining-admin-service/src/infrastructure/kafka/cdc-sync.service.ts
+++ b/backend/services/mining-admin-service/src/infrastructure/kafka/cdc-sync.service.ts
@@ -543,23 +543,36 @@ export class CdcSyncService implements OnModuleInit {
     const accountType = payload.accountType;
     const regionCode = payload.regionCode || null;
 
-    // 使用 findFirst + create/update 替代 upsert，因为 regionCode 可以为 null
-    const existing = await tx.syncedSystemContribution.findFirst({
+    // 查找所有匹配的记录（处理可能存在的重复记录情况）
+    // 注意：由于 PostgreSQL 中 NULL != NULL，唯一约束在 regionCode 为 NULL 时不生效
+    const existingRecords = await tx.syncedSystemContribution.findMany({
       where: {
         accountType,
         regionCode: regionCode === null ? { equals: null } : regionCode,
       },
+      orderBy: { syncedAt: 'asc' },
     });
 
-    if (existing) {
+    if (existingRecords.length > 0) {
       await tx.syncedSystemContribution.update({
-        where: { id: existing.id },
+        where: { id: existingRecords[0].id },
         data: {
           name: payload.name,
           contributionBalance: payload.contributionBalance,
           contributionNeverExpires: payload.contributionNeverExpires,
         },
       });
+
+      // 删除重复记录
+      if (existingRecords.length > 1) {
+        const duplicateIds = existingRecords.slice(1).map(r => r.id);
+        await tx.syncedSystemContribution.deleteMany({
+          where: { id: { in: duplicateIds } },
+        });
+        this.logger.warn(
+          `Deleted ${duplicateIds.length} duplicate system contribution records for ${accountType}:${regionCode}`,
+        );
+      }
     } else {
       await tx.syncedSystemContribution.create({
         data: {
@@ -578,28 +591,44 @@ export class CdcSyncService implements OnModuleInit {
    * 来自 contribution-service 的系统账户（运营、省、市、总部）算力同步
    * accountType: OPERATION / PROVINCE / CITY / HEADQUARTERS
    * regionCode: 省/市代码，如 440000, 440100
+   *
+   * 注意：由于 PostgreSQL 中 NULL != NULL，@@unique([accountType, regionCode]) 约束
+   * 在 regionCode 为 NULL 时不会阻止重复插入。因此需要在代码层面确保唯一性。
    */
   private async handleSystemAccountSynced(event: ServiceEvent, tx: TransactionClient): Promise<void> {
     const { payload } = event;
     const accountType = payload.accountType; // OPERATION / PROVINCE / CITY / HEADQUARTERS
     const regionCode = payload.regionCode || null;
 
-    // 使用 findFirst + create/update 替代 upsert，因为 regionCode 可以为 null
-    const existing = await tx.syncedSystemContribution.findFirst({
+    // 查找所有匹配的记录（处理可能存在的重复记录情况）
+    const existingRecords = await tx.syncedSystemContribution.findMany({
       where: {
         accountType,
         regionCode: regionCode === null ? { equals: null } : regionCode,
       },
+      orderBy: { syncedAt: 'asc' }, // 保留最早创建的记录
     });
 
-    if (existing) {
+    if (existingRecords.length > 0) {
+      // 更新第一条记录
       await tx.syncedSystemContribution.update({
-        where: { id: existing.id },
+        where: { id: existingRecords[0].id },
         data: {
           name: payload.name,
           contributionBalance: payload.contributionBalance,
         },
       });
+
+      // 如果存在重复记录，删除多余的（只保留第一条）
+      if (existingRecords.length > 1) {
+        const duplicateIds = existingRecords.slice(1).map(r => r.id);
+        await tx.syncedSystemContribution.deleteMany({
+          where: { id: { in: duplicateIds } },
+        });
+        this.logger.warn(
+          `Deleted ${duplicateIds.length} duplicate system contribution records for ${accountType}:${regionCode}`,
+        );
+      }
     } else {
       await tx.syncedSystemContribution.create({
         data: {