diff --git a/README.md b/README.md
index 67e7742..273d3fc 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@
 ## Description
 
 A chat-bot operator returns answer in text given input text.
-This operator is implemented with GPT models from [OpenAI](https://platform.openai.com/docs/guides/embeddings).
+This operator is implemented with Completion method from [OpenAI](https://platform.openai.com/docs/models/overview).
 Please note you need an [OpenAI API key](https://platform.openai.com/account/api-keys) to access OpenAI.
 
 <br />
@@ -43,8 +43,8 @@ Create the operator via the following factory method:
 
 ***model_name***: *str*
 
-The model name in string, defaults to 'text-davinci-003'. Supported model names:
-- text-davinci-003
+The model name in string, defaults to 'text-davinci-003'.
+Refer to [OpenAI List Models](https://platform.openai.com/docs/api-reference/models/list) for all supported model names.
 
 ***api_key***: *str=None*
 
@@ -55,7 +55,7 @@ The OpenAI API key in string, defaults to None.
 ## Interface
 
 The operator takes a piece of text in string as input.
-It returns a text emabedding in numpy.ndarray.
+It returns a text answer.
 
 ***\_\_call\_\_(txt)***
 
diff --git a/openai_qa.py b/openai_qa.py
index 31fac6e..b6bd0ec 100644
--- a/openai_qa.py
+++ b/openai_qa.py
@@ -19,18 +19,18 @@ from towhee.operator.base import PyOperator
 
 
 class OpenaiQA(PyOperator):
-    def __init__(self, model_name='text-davinci-003', api_key=None):
-        self._engine = model_name
+    def __init__(self, model_name='text-davinci-003', api_key=None, max_token=50):
+        self._model = model_name
         self._api_key = api_key
+        self._max_token = max_token
 
     # @retry(wait=wait_random_exponential(min=1, max=20), stop=stop_after_attempt(6))
     def _call(self, prompt):
-        prompt = prompt.replace("\n", " ")
         response = openai.Completion.create(
             api_key=self._api_key,
-            engine=self._engine,
+            model=self._model,
             prompt=prompt,
-            max_tokens=1024,
+            max_tokens=self._max_token,
             n=1,
             stop=None,
             temperature=0.3,
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..dab6363
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+openai>=2.7
\ No newline at end of file