diff --git a/paddlespeech/audio/transform/perturb.py b/paddlespeech/audio/transform/perturb.py
index 78b8d2c3..757a2f1b 100644
--- a/paddlespeech/audio/transform/perturb.py
+++ b/paddlespeech/audio/transform/perturb.py
@@ -99,7 +99,7 @@ class SoundHDF5File():
     def __contains__(self, item):
         return item in self.file
 
-    def __len__(self, item):
+    def __len__(self):
         return len(self.file)
 
     def __enter__(self):
diff --git a/paddlespeech/s2t/io/reader.py b/paddlespeech/s2t/io/reader.py
index be643cc7..d433a643 100644
--- a/paddlespeech/s2t/io/reader.py
+++ b/paddlespeech/s2t/io/reader.py
@@ -404,7 +404,7 @@ class SoundHDF5File():
     def __contains__(self, item):
         return item in self.file
 
-    def __len__(self, item):
+    def __len__(self):
         return len(self.file)
 
     def __enter__(self):