diff --git a/backend/services/reward-service/src/domain/services/reward-calculation.service.ts b/backend/services/reward-service/src/domain/services/reward-calculation.service.ts
index f2d6632e..8c012624 100644
--- a/backend/services/reward-service/src/domain/services/reward-calculation.service.ts
+++ b/backend/services/reward-service/src/domain/services/reward-calculation.service.ts
@@ -66,6 +66,16 @@ const SHARE_RIGHT_POOL_USER_ID = BigInt(-5);
 export class RewardCalculationService {
   private readonly logger = new Logger(RewardCalculationService.name);
 
+  /**
+   * 将 accountSequence 转换为 userId
+   * accountSequence 格式: D25121400002 (用户) / S0000000001 (系统) / 9440000 (省系统)
+   * 如果以字母开头，去掉第一个字符后转为 BigInt
+   */
+  private parseAccountSequenceToUserId(accountSequence: string): bigint {
+    const numericPart = /^[a-zA-Z]/i.test(accountSequence) ? accountSequence.slice(1) : accountSequence;
+    return BigInt(numericPart);
+  }
+
   constructor(
     @Inject(REFERRAL_SERVICE_CLIENT)
     private readonly referralService: IReferralServiceClient,
@@ -432,7 +442,7 @@ export class RewardCalculationService {
 
       rewards.push(
         RewardLedgerEntry.createSettleable({
-          userId: BigInt(item.accountSequence),
+          userId: this.parseAccountSequenceToUserId(item.accountSequence),
           accountSequence: item.accountSequence,
           rewardSource,
           usdtAmount: itemUsdtAmount,
@@ -488,7 +498,7 @@ export class RewardCalculationService {
 
       rewards.push(
         RewardLedgerEntry.createSettleable({
-          userId: BigInt(item.accountSequence),
+          userId: this.parseAccountSequenceToUserId(item.accountSequence),
           accountSequence: item.accountSequence,
           rewardSource,
           usdtAmount: itemUsdtAmount,
@@ -544,7 +554,7 @@ export class RewardCalculationService {
 
       rewards.push(
         RewardLedgerEntry.createSettleable({
-          userId: BigInt(item.accountSequence),
+          userId: this.parseAccountSequenceToUserId(item.accountSequence),
           accountSequence: item.accountSequence,
           rewardSource,
           usdtAmount: itemUsdtAmount,
@@ -600,7 +610,7 @@ export class RewardCalculationService {
 
       rewards.push(
         RewardLedgerEntry.createSettleable({
-          userId: BigInt(item.accountSequence),
+          userId: this.parseAccountSequenceToUserId(item.accountSequence),
           accountSequence: item.accountSequence,
           rewardSource,
           usdtAmount: itemUsdtAmount,
@@ -656,7 +666,7 @@ export class RewardCalculationService {
 
       rewards.push(
         RewardLedgerEntry.createSettleable({
-          userId: BigInt(item.accountSequence),
+          userId: this.parseAccountSequenceToUserId(item.accountSequence),
           accountSequence: item.accountSequence,
           rewardSource,
           usdtAmount: itemUsdtAmount,