diff --git a/README.md b/README.md
index 78c368b..30e9035 100644
--- a/README.md
+++ b/README.md
@@ -23,9 +23,9 @@ A proxy for YOU Chat.
 
 ## Limitations 限制
 
-Only Anthropic API format is supported. The model is hardcoded Claude 3 Opus.
+Only Anthropic API format is supported. Change the model name to use different models (default claude_3_opus)
 
-只支持A社的API格式，模型是写死了的 Claude 3 Opus
+只支持A社的API格式，默认模型为 claude_3_opus。
 
 Messages will be squashed into question: ... answer: ... format.
 
diff --git a/index.js b/index.js
index 10e8dc1..cb721bf 100644
--- a/index.js
+++ b/index.js
@@ -6,7 +6,7 @@ const { ProxyAgent } = require("proxy-agent");
 const agent = new ProxyAgent();
 const app = express();
 const axios = require("axios");
-const port = 8080;
+const port = process.env.PORT || 8080;
 const validApiKey = process.env.PASSWORD;
 
 // import config.js
@@ -167,7 +167,7 @@ app.post("/v1/messages", apiKeyAuth, (req, res) => {
 							chatId: traceId,
 							traceId: `${traceId}|${msgid}|${new Date().toISOString()}`,
 							conversationTurnId: msgid,
-							selectedAiModel: "claude_3_opus",
+							selectedAiModel: process.env.AI_MODEL || "claude_3_opus",
 							selectedChatMode: "custom",
 							pastChatLength: userMessage.length,
 							queryTraceId: traceId,
diff --git a/start.bat b/start.bat
index dd59036..1086e20 100644
--- a/start.bat
+++ b/start.bat
@@ -1,5 +1,7 @@
 call npm install
 set PASSWORD=
 set https_proxy=
+set PORT=8080
+set AI_MODEL=claude_3_opus
 node index
 pause
\ No newline at end of file
diff --git a/usage.md b/usage.md
index c655c25..03cdeba 100644
--- a/usage.md
+++ b/usage.md
@@ -35,6 +35,8 @@ module.exports = {
 
     （可选）如果需要，可以设置代理。
 
+    （可选）如果需要，可以修改使用的模型。但是仍然建议使用opus，因为其他未经测试。
+
 8. 启动 start.bat
 
 9. 酒馆中选择 Claude，反向代理地址填 http://127.0.0.1:8080/v1 **反代密码必须填, 同时打开流式传输**，随便什么都可以（除非你在第7步设置了PASSWORD）。
@@ -49,6 +51,27 @@ module.exports = {
 
 欲知详细代理格式，请查阅 https://www.npmjs.com/package/proxy-from-env
 
+# 修改模型
+
+修改`AI_MODEL`环境变量可以切换模型，支持的模型名字如下 (请参考官网获取最新模型):
+
+```
+gpt_4o
+gpt_4_turbo
+gpt_4
+claude_3_opus
+claude_3_sonnet
+claude_3_haiku
+claude_2
+llama3
+gemini_pro
+gemini_1_5_pro
+databricks_dbrx_instruct
+command_r
+command_r_plus
+zephyr
+```
+
 ## 注意事项
 
 出现 403 错误请重新抓 COOKIE 或者更换代理出口 IP。
@@ -91,6 +114,8 @@ module.exports = {
    
    (Optional) You can set the proxy in start.bat. See below.
 
+   (Optional) You may change the model to use, but only claude_3_opus is tested.
+
 8. Start start.bat
 
 9. Select Claude in the Tavern and put http://127.0.0.1:8080/v1 as the address of the reverse proxy. **Use any random string for password, also turn on Streaming** (unless you set PASSWORD in step 7).
@@ -101,6 +126,29 @@ module.exports = {
 
 Use the `https_proxy` env to set custom proxy. Refer to https://www.npmjs.com/package/proxy-from-env for detail.
 
+# Change model
+
+Change `AI_MODEL` env to switch between models.
+
+Supported model names (refer to you.com website for latest models):
+
+```
+gpt_4o
+gpt_4_turbo
+gpt_4
+claude_3_opus
+claude_3_sonnet
+claude_3_haiku
+claude_2
+llama3
+gemini_pro
+gemini_1_5_pro
+databricks_dbrx_instruct
+command_r
+command_r_plus
+zephyr
+```
+
 ## Caution
 
 If you get 403 errors, consider getting the cookie again or changing your IP.