diff --git a/lmdeploy/pytorch/engine/mp_engine/ray_engine.py b/lmdeploy/pytorch/engine/mp_engine/ray_engine.py
index 0d133abfad..cfc7a53a37 100644
--- a/lmdeploy/pytorch/engine/mp_engine/ray_engine.py
+++ b/lmdeploy/pytorch/engine/mp_engine/ray_engine.py
@@ -1,11 +1,12 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 import asyncio
+from collections import defaultdict
 from typing import Dict
 
 import ray
 from ray.util.scheduling_strategies import PlacementGroupSchedulingStrategy
 
-from lmdeploy.messages import PytorchEngineConfig
+from lmdeploy.messages import EngineOutput, PytorchEngineConfig
 from lmdeploy.pytorch import envs as _envs
 from lmdeploy.pytorch.ray import RayContext, get_device_str, get_resource_kwargs
 from lmdeploy.utils import get_logger
@@ -35,6 +36,7 @@ def __init__(self,
         self._stream_id = 0
         self._stream_aiter = dict()
         self._stream_task = dict()
+        self._engine_output_offset = defaultdict(int)
 
     async def _stream_task_wrapper(self, stream_id: int, func: str, *args, **kwargs):
         """Create a stream task."""
@@ -67,6 +69,22 @@ async def get_stream_task_result(self, stream_id: int):
         result, stopped = self._stream_aiter[stream_id][1]
         event.clear()
 
+        def __return_engine_output_incrementally(result):
+            if not isinstance(result, EngineOutput):
+                return
+            old_offset = self._engine_output_offset[stream_id]
+            new_offset = len(result.token_ids)
+            if old_offset:
+                if result.token_ids:
+                    result.token_ids = result.token_ids[old_offset:]
+                if result.logprobs:
+                    result.logprobs = result.logprobs[old_offset:]
+            self._engine_output_offset[stream_id] = new_offset
+            if stopped:
+                self._engine_output_offset.pop(stream_id, None)
+
+        __return_engine_output_incrementally(result)
+
         if stopped:
             self._stream_aiter.pop(stream_id, None)
             self._stream_task.pop(stream_id, None)
@@ -92,6 +110,7 @@ def __init__(self, model_path: str, engine_config: PytorchEngineConfig = None, *
 
         self.worker = self._create_worker(model_path, engine_config, log_level=logger.level, **kwargs)
         super().__init__()
+        self._engine_output = defaultdict(lambda: EngineOutput(status=None, token_ids=[], num_token=0, logprobs=[]))
 
     def _init_ray(self, engine_config: PytorchEngineConfig = None):
         """Initialize Ray."""
@@ -142,9 +161,22 @@ async def _collective_rpc_streaming_async(self, func, *args, **kwargs):
         # ray generator would try cache every result, which is too verbose.
         stream_id = await self._collective_rpc_async('create_stream_task', func, *args, **kwargs)
 
+        def __merge_engine_output(result):
+            if not isinstance(result, EngineOutput):
+                return
+
+            output = self._engine_output[stream_id]
+            output.token_ids.extend(result.token_ids or [])
+            output.logprobs.extend(result.logprobs or [])
+            result.token_ids = output.token_ids or []
+            result.logprobs = output.logprobs or None
+            if stopped:
+                self._engine_output.pop(stream_id, None)
+
         stopped = False
         while not stopped:
             result, stopped = await self._collective_rpc_async('get_stream_task_result', stream_id)
+            __merge_engine_output(result)
             yield result
 
     def close(self) -> None: