diff --git a/metagpt/provider/openai_api.py b/metagpt/provider/openai_api.py
index 6d4e1b406..14347f20c 100644
--- a/metagpt/provider/openai_api.py
+++ b/metagpt/provider/openai_api.py
@@ -276,6 +276,8 @@ class OpenAIGPTAPI(BaseGPTAPI, RateLimiter):
     @staticmethod
     def split_texts(text: str, window_size) -> List[str]:
         """Splitting long text into sliding windows text"""
+        if window_size <= 0:
+            window_size = OpenAIGPTAPI.DEFAULT_TOKEN_SIZE
         total_len = len(text)
         if total_len <= window_size:
             return [text]
@@ -283,18 +285,19 @@ class OpenAIGPTAPI(BaseGPTAPI, RateLimiter):
         padding_size = 20 if window_size > 20 else 0
         windows = []
         idx = 0
+        data_len = window_size - padding_size
         while idx < total_len:
-            data_len = window_size - padding_size
-            if data_len + idx > total_len:
+            if window_size + idx > total_len:  # 不足一个滑窗
                 windows.append(text[idx:])
                 break
-            w = text[idx:data_len]
+            # 每个窗口少算padding_size自然就可实现滑窗功能, 比如: [1, 2, 3, 4, 5, 6, 7, ....]
+            # window_size=3, padding_size=1：
+            # [1, 2, 3], [3, 4, 5], [5, 6, 7], ....
+            #   idx=2,  |  idx=5   |  idx=8  | ...
+            w = text[idx : idx + window_size]
             windows.append(w)
             idx += data_len
-        for i in range(len(windows)):
-            if i + 1 == len(windows):
-                break
-            windows[i] += windows[i + 1][0:padding_size]
+
         return windows
 
     @staticmethod
@@ -348,6 +351,7 @@ class OpenAIGPTAPI(BaseGPTAPI, RateLimiter):
         raise openai.error.OpenAIError("Exceeds the maximum retries")
 
     MAX_TRY = 5
+    DEFAULT_TOKEN_SIZE = 500
 
 
 if __name__ == "__main__":