diff --git a/paddlespeech/server/engine/asr/online/python/asr_engine.py b/paddlespeech/server/engine/asr/online/python/asr_engine.py
index 4df38f09..96d4823e 100644
--- a/paddlespeech/server/engine/asr/online/python/asr_engine.py
+++ b/paddlespeech/server/engine/asr/online/python/asr_engine.py
@@ -21,10 +21,10 @@ import paddle
 from numpy import float32
 from yacs.config import CfgNode
 
+from paddlespeech.audio.transform.transformation import Transformation
 from paddlespeech.cli.asr.infer import ASRExecutor
 from paddlespeech.cli.log import logger
 from paddlespeech.resource import CommonTaskResource
-from paddlespeech.audio.transform.transformation import Transformation
 from paddlespeech.s2t.frontend.featurizer.text_featurizer import TextFeaturizer
 from paddlespeech.s2t.modules.ctc import CTCDecoder
 from paddlespeech.s2t.utils.tensor_utils import add_sos_eos
@@ -130,8 +130,8 @@ class PaddleASRConnectionHanddler:
 
         ## conformer
         # cache for conformer online
-        self.att_cache = paddle.zeros([0,0,0,0])
-        self.cnn_cache = paddle.zeros([0,0,0,0])
+        self.att_cache = paddle.zeros([0, 0, 0, 0])
+        self.cnn_cache = paddle.zeros([0, 0, 0, 0])
 
         self.encoder_out = None
         # conformer decoding state
@@ -474,9 +474,10 @@ class PaddleASRConnectionHanddler:
             # cur chunk
             chunk_xs = self.cached_feat[:, cur:end, :]
             # forward chunk
-            (y, self.att_cache, self.cnn_cache) = self.model.encoder.forward_chunk(
-                 chunk_xs, self.offset, required_cache_size,
-                 self.att_cache, self.cnn_cache)
+            (y, self.att_cache,
+             self.cnn_cache) = self.model.encoder.forward_chunk(
+                 chunk_xs, self.offset, required_cache_size, self.att_cache,
+                 self.cnn_cache, paddle.ones([0, 0, 0], dtype=paddle.bool))
             outputs.append(y)
 
             # update the global offset, in decoding frame unit