diff --git a/bls-oldrcu-heartbeat-backend/src/buffer/heartbeatBuffer.js b/bls-oldrcu-heartbeat-backend/src/buffer/heartbeatBuffer.js
index 5eeb31b..7010e0f 100644
--- a/bls-oldrcu-heartbeat-backend/src/buffer/heartbeatBuffer.js
+++ b/bls-oldrcu-heartbeat-backend/src/buffer/heartbeatBuffer.js
@@ -12,6 +12,7 @@ export class HeartbeatBuffer {
    * @param {Object} options
    * @param {number} [options.flushInterval=5000] - flush 间隔 (ms)
    * @param {number} [options.maxBufferSize=10000] - 缓冲区上限触发强制 flush
+   * @param {number} [options.flushBatchSize=5000] - 单次 flush 最大落库条数
    * @param {import('../redis/redisIntegration.js').RedisIntegration} [options.redisIntegration]
    * @param {import('../utils/metricCollector.js').MetricCollector} [options.metricCollector]
    * @param {() => number} [options.now] - 测试用时间函数
@@ -20,6 +21,7 @@ export class HeartbeatBuffer {
     this.dbManager = dbManager;
     this.flushInterval = options.flushInterval || 5000;
     this.maxBufferSize = options.maxBufferSize || 10000;
+    this.flushBatchSize = options.flushBatchSize > 0 ? options.flushBatchSize : 5000;
     this.redisIntegration = options.redisIntegration || null;
     this.metricCollector = options.metricCollector || null;
     this.now = options.now || (() => Date.now());
@@ -127,9 +129,13 @@ export class HeartbeatBuffer {
     if (this.isFlushing) return;
     this.isFlushing = true;
 
-    const writableEntries = Array.from(this.buffer.entries());
-    for (const [key] of writableEntries) {
+    const writableEntries = [];
+    for (const [key, row] of this.buffer.entries()) {
+      writableEntries.push([key, row]);
       this.buffer.delete(key);
+      if (writableEntries.length >= this.flushBatchSize) {
+        break;
+      }
     }
 
     const rows = writableEntries.map(([, row]) => row);
@@ -180,6 +186,8 @@ export class HeartbeatBuffer {
       this.isFlushing = false;
       if (this.buffer.size >= this.maxBufferSize) {
         this.flush();
+      } else if (this.buffer.size >= this.flushBatchSize) {
+        this.flush();
       } else if (this.buffer.size > 0 && !this.timer) {
         this._scheduleFlush(this.flushInterval);
       }
diff --git a/bls-oldrcu-heartbeat-backend/src/config/config.js b/bls-oldrcu-heartbeat-backend/src/config/config.js
index 3ae8c2c..03d9131 100644
--- a/bls-oldrcu-heartbeat-backend/src/config/config.js
+++ b/bls-oldrcu-heartbeat-backend/src/config/config.js
@@ -58,6 +58,7 @@ export const config = {
     database: process.env.POSTGRES_DATABASE_G5,
     max: parseNumber(process.env.POSTGRES_MAX_CONNECTIONS, 6),
     idleTimeoutMillis: parseNumber(process.env.POSTGRES_IDLE_TIMEOUT_MS_G5, 30000),
+    upsertChunkSize: parseNumber(process.env.DB_UPSERT_CHUNK_SIZE, 5000),
     schema: 'room_status',
     table: 'room_status_moment_g5'
   },
@@ -72,6 +73,7 @@ export const config = {
   },
   heartbeatBuffer: {
     flushInterval: 5000,
-    maxBufferSize: 10000
+    maxBufferSize: 10000,
+    flushBatchSize: parseNumber(process.env.HEARTBEAT_FLUSH_BATCH_SIZE, 5000)
   }
 };
diff --git a/bls-oldrcu-heartbeat-backend/src/db/heartbeatDbManager.js b/bls-oldrcu-heartbeat-backend/src/db/heartbeatDbManager.js
index d6a490c..ebc56a2 100644
--- a/bls-oldrcu-heartbeat-backend/src/db/heartbeatDbManager.js
+++ b/bls-oldrcu-heartbeat-backend/src/db/heartbeatDbManager.js
@@ -5,6 +5,9 @@ const { Pool } = pg;
 
 const SMALLINT_MIN = -32768;
 const SMALLINT_MAX = 32767;
+const PARAMS_PER_ROW = 4;
+const PG_MAX_BIND_PARAMS = 65535;
+const MAX_ROWS_PER_STATEMENT = Math.floor(PG_MAX_BIND_PARAMS / PARAMS_PER_ROW);
 
 const normalizeHotelId = (hotelId) => {
   const parsed = Number(hotelId);
@@ -34,25 +37,35 @@ export class HeartbeatDbManager {
     this.schema = dbConfig.schema;
     this.table = dbConfig.table;
     this.fullTableName = `${this.schema}.${this.table}`;
+    const configuredChunkSize = Number(dbConfig.upsertChunkSize);
+    const fallbackChunkSize = 5000;
+    const normalizedChunkSize = Number.isInteger(configuredChunkSize) && configuredChunkSize > 0
+      ? configuredChunkSize
+      : fallbackChunkSize;
+    this.upsertChunkSize = Math.min(normalizedChunkSize, MAX_ROWS_PER_STATEMENT);
   }
 
   /**
    * Batch upsert heartbeat rows.
-   * ON CONFLICT (hotel_id, room_id) → upsert latest heartbeat only.
-   * If the row already exists, only overwrite it when EXCLUDED.ts_ms is not older
-   * than the current row, preventing out-of-order Kafka messages from rolling data back.
+   * 为避免 PostgreSQL bind 参数上限，按 upsertChunkSize 分片执行。
     * @param {Array<{ts_ms: number, hotel_id: string, room_id: string, device_id: string}>} rows
    */
   async upsertBatch(rows) {
     if (!rows || rows.length === 0) return;
 
+    for (let start = 0; start < rows.length; start += this.upsertChunkSize) {
+      const chunk = rows.slice(start, start + this.upsertChunkSize);
+      await this._upsertChunk(chunk);
+    }
+  }
+
+  async _upsertChunk(rows) {
     const values = [];
     const placeholders = [];
-    const colsPerRow = 4;
 
     for (let i = 0; i < rows.length; i++) {
       const row = rows[i];
-      const offset = i * colsPerRow;
+      const offset = i * PARAMS_PER_ROW;
       values.push(normalizeHotelId(row.hotel_id), row.room_id, row.device_id, row.ts_ms);
       placeholders.push(
         `($${offset + 1}::smallint, $${offset + 2}, $${offset + 3}, $${offset + 4}, 1)`
@@ -77,7 +90,8 @@ export class HeartbeatDbManager {
     } catch (error) {
       logger.error('Database upsert failed', {
         error: error?.message,
-        rowCount: rows.length
+        rowCount: rows.length,
+        bindParamCount: values.length
       });
       throw error;
     }
diff --git a/bls-oldrcu-heartbeat-backend/src/index.js b/bls-oldrcu-heartbeat-backend/src/index.js
index 3877d12..ccbc8d3 100644
--- a/bls-oldrcu-heartbeat-backend/src/index.js
+++ b/bls-oldrcu-heartbeat-backend/src/index.js
@@ -42,6 +42,7 @@ const bootstrap = async () => {
   const heartbeatBuffer = new HeartbeatBuffer(dbManager, {
     flushInterval: config.heartbeatBuffer.flushInterval,
     maxBufferSize: config.heartbeatBuffer.maxBufferSize,
+    flushBatchSize: config.heartbeatBuffer.flushBatchSize,
     redisIntegration,
     metricCollector
   });
diff --git a/bls-oldrcu-heartbeat-backend/tests/heartbeat_buffer.test.js b/bls-oldrcu-heartbeat-backend/tests/heartbeat_buffer.test.js
index cf55800..cc8fdd1 100644
--- a/bls-oldrcu-heartbeat-backend/tests/heartbeat_buffer.test.js
+++ b/bls-oldrcu-heartbeat-backend/tests/heartbeat_buffer.test.js
@@ -86,4 +86,28 @@ describe('HeartbeatBuffer', () => {
     expect(rows[0].ts_ms).toBe(3000);
     expect(rows[0].device_id).toBe('dev-c');
   });
+
+  it('should flush in chunks when buffer size exceeds flushBatchSize', async () => {
+    buffer = new HeartbeatBuffer(dbManager, {
+      flushInterval: 100000,
+      maxBufferSize: 99999,
+      flushBatchSize: 2,
+      now: () => nowTs
+    });
+
+    buffer.add({ ts_ms: 1000, hotel_id: '1', room_id: '101', device_id: 'dev-a' });
+    buffer.add({ ts_ms: 2000, hotel_id: '1', room_id: '102', device_id: 'dev-b' });
+    buffer.add({ ts_ms: 3000, hotel_id: '1', room_id: '103', device_id: 'dev-c' });
+
+    await buffer.flush();
+
+    expect(dbManager.upsertBatch).toHaveBeenCalledTimes(1);
+    expect(dbManager.upsertBatch.mock.calls[0][0]).toHaveLength(2);
+
+    await buffer.flush();
+
+    expect(dbManager.upsertBatch).toHaveBeenCalledTimes(2);
+    expect(dbManager.upsertBatch.mock.calls[1][0]).toHaveLength(1);
+    expect(dbManager.upsertBatch.mock.calls[1][0][0].room_id).toBe('103');
+  });
 });
diff --git a/bls-oldrcu-heartbeat-backend/tests/heartbeat_db_manager.test.js b/bls-oldrcu-heartbeat-backend/tests/heartbeat_db_manager.test.js
index 191dcbf..d464e7b 100644
--- a/bls-oldrcu-heartbeat-backend/tests/heartbeat_db_manager.test.js
+++ b/bls-oldrcu-heartbeat-backend/tests/heartbeat_db_manager.test.js
@@ -70,4 +70,33 @@ describe('HeartbeatDbManager', () => {
     const [, values] = queryMock.mock.calls[0];
     expect(values).toEqual([0, '101', 'dev-a', 1000]);
   });
+
+  it('should split large batches into multiple upsert queries', async () => {
+    const { HeartbeatDbManager } = await import('../src/db/heartbeatDbManager.js');
+    const manager = new HeartbeatDbManager({
+      host: '127.0.0.1',
+      port: 5432,
+      user: 'postgres',
+      password: 'secret',
+      database: 'demo',
+      max: 1,
+      idleTimeoutMillis: 1000,
+      upsertChunkSize: 2,
+      schema: 'room_status',
+      table: 'room_status_moment_g5'
+    });
+
+    await manager.upsertBatch([
+      { hotel_id: '1', room_id: '101', device_id: 'dev-a', ts_ms: 1000 },
+      { hotel_id: '1', room_id: '102', device_id: 'dev-b', ts_ms: 1001 },
+      { hotel_id: '1', room_id: '103', device_id: 'dev-c', ts_ms: 1002 },
+      { hotel_id: '1', room_id: '104', device_id: 'dev-d', ts_ms: 1003 },
+      { hotel_id: '1', room_id: '105', device_id: 'dev-e', ts_ms: 1004 }
+    ]);
+
+    expect(queryMock).toHaveBeenCalledTimes(3);
+    expect(queryMock.mock.calls[0][1]).toEqual([1, '101', 'dev-a', 1000, 1, '102', 'dev-b', 1001]);
+    expect(queryMock.mock.calls[1][1]).toEqual([1, '103', 'dev-c', 1002, 1, '104', 'dev-d', 1003]);
+    expect(queryMock.mock.calls[2][1]).toEqual([1, '105', 'dev-e', 1004]);
+  });
 });
\ No newline at end of file