diff --git a/tools/tokenizer.py b/tools/tokenizer.py
index bc92ea4..9a969ad 100644
--- a/tools/tokenizer.py
+++ b/tools/tokenizer.py
@@ -13,13 +13,13 @@ model_path = os.path.join(current_dir, "V7_sft.model")
 tokenizer = InternLMTokenizer(vocab_file=model_path)
 
 
-def write_bin(context: str, bin_output_path: str) -> None:
+def write_bin(context: str, bin_file) -> None:
     """
     Write bin file based on the context.
 
     Args:
         context (str): the context of raw file.
-        bin_output_path (str): the path for output bin file.
+        bin_file (file handler): the opened bin file.
 
     Example:
     >>> write_bin("今天天气晴朗适合出门散步", "out.bin") # the output file format is 'txt'
@@ -34,9 +34,8 @@ def write_bin(context: str, bin_output_path: str) -> None:
     # encode the data into bytes to save
     saved_bin = str.encode(json.dumps(data) + "\n")
 
-    # write bytes into bin path
-    with open(bin_output_path, "ab") as f:
-        f.write(saved_bin)
+    # write bytes into bin_file
+    bin_file.write(saved_bin)
 
 
 def prepare_meta(bin_output_path: str):
@@ -90,14 +89,14 @@ def text2bin(text_input_path: str, bin_output_path: str):
     assert file_format in ['txt', 'json', 'jsonl'], \
         print("Invalid input file type. Currently support `txt`, `json` and `jsonl`.")
 
-    with open(text_input_path, "r") as text_file:
+    with open(text_input_path, "r") as text_file, open(bin_output_path, "ab") as bin_file:
         if file_format == 'txt':
             for line in text_file:
                 # Strip any leading/trailing whitespace
                 stripped_line = line.strip()
                 if stripped_line:
                     # Pass each line to the write_bin function
-                    write_bin(stripped_line, bin_output_path)
+                    write_bin(stripped_line, bin_file)
 
         elif file_format == 'json':
             data = json.load(text_file)
@@ -106,12 +105,12 @@ def text2bin(text_input_path: str, bin_output_path: str):
                 # the type of record is dict, transfer the dict into str
                 context = json.dumps(record)
                 # encode the str and write into bin
-                write_bin(context, bin_output_path)
+                write_bin(context, bin_file)
         
         elif file_format == 'jsonl':
             for line in text_file:
                 # encode the str and write into bin
-                write_bin(line, bin_output_path)
+                write_bin(line, bin_file)
 
 
 def parse_args():