diff --git a/python/sglang/srt/managers/schedule_batch.py b/python/sglang/srt/managers/schedule_batch.py
index 5fd830afe..66e6ae44e 100644
--- a/python/sglang/srt/managers/schedule_batch.py
+++ b/python/sglang/srt/managers/schedule_batch.py
@@ -692,9 +692,15 @@ class Req:
             self.surr_offset = max(
                 self.read_offset - INIT_INCREMENTAL_DETOKENIZATION_OFFSET, 0
             )
+            self.surr_and_decode_ids = (
+                self.origin_input_ids_unpadded[self.surr_offset :] + self.output_ids
+            )
+            self.cur_decode_ids_len = len(self.output_ids)
+        else:
+            self.surr_and_decode_ids.extend(self.output_ids[self.cur_decode_ids_len :])
+            self.cur_decode_ids_len = len(self.output_ids)
 
-        all_ids = self.origin_input_ids_unpadded + self.output_ids
-        return all_ids[self.surr_offset :], self.read_offset - self.surr_offset
+        return self.surr_and_decode_ids, self.read_offset - self.surr_offset
 
     def check_finished(self):
         if self.finished():