diff --git a/paraformer/runtime/python/utils/preprocess.py b/paraformer/runtime/python/utils/preprocess.py
index 149b433..b1df1a7 100644
--- a/paraformer/runtime/python/utils/preprocess.py
+++ b/paraformer/runtime/python/utils/preprocess.py
@@ -382,6 +382,7 @@ def cache_reset(self):
         self.fbank_fn = knf.OnlineFbank(self.opts)
         self.reserve_waveforms = None
         self.input_cache = None
+        self.waveform = None
         self.lfr_splice_cache = []