diff --git a/src/app.tsx b/src/app.tsx
index c2e016c..20d3ac7 100644
--- a/src/app.tsx
+++ b/src/app.tsx
@@ -3,6 +3,8 @@ import "./global.css";
 
 import ChatGPT, { Message, ChunkMessage } from "./chatgpt";
 import { createRef } from "preact";
+import Settings from "./settings";
+import getDefaultParams from "./getDefaultParam";
 
 export interface ChatStore {
   systemMessageContent: string;
@@ -16,49 +18,23 @@ export interface ChatStore {
   streamMode: boolean;
 }
 
-const defaultAPIKEY = () => {
-  const queryParameters = new URLSearchParams(window.location.search);
-  const key = queryParameters.get("key");
-  return key;
-};
-
-const defaultSysMessage = () => {
-  const queryParameters = new URLSearchParams(window.location.search);
-  const sys = queryParameters.get("sys");
-  return sys;
-};
-
-const defaultAPIEndpoint = () => {
-  const queryParameters = new URLSearchParams(window.location.search);
-  const sys = queryParameters.get("api");
-  return sys;
-};
-
-const defauleMode = () => {
-  const queryParameters = new URLSearchParams(window.location.search);
-  const sys = queryParameters.get("mode");
-  if (sys === "stream") return true;
-  if (sys === "fetch") return false;
-  return undefined;
-};
-
 const _defaultAPIEndpoint = "https://api.openai.com/v1/chat/completions";
-export const newChatStore = (
+const newChatStore = (
   apiKey = "",
   systemMessageContent = "你是一个猫娘，你要模仿猫娘的语气说话",
   apiEndpoint = _defaultAPIEndpoint,
   streamMode = true
 ): ChatStore => {
   return {
-    systemMessageContent: defaultSysMessage() || systemMessageContent,
+    systemMessageContent: getDefaultParams("sys", systemMessageContent),
     history: [],
     postBeginIndex: 0,
     tokenMargin: 1024,
     totalTokens: 0,
     maxTokens: 4096,
-    apiKey: defaultAPIKEY() || apiKey,
-    apiEndpoint: defaultAPIEndpoint() || apiEndpoint,
-    streamMode: defauleMode() ?? streamMode,
+    apiKey: getDefaultParams("key", apiKey),
+    apiEndpoint: getDefaultParams("api", apiEndpoint),
+    streamMode: getDefaultParams("mode", streamMode),
   };
 };
 
@@ -213,16 +189,16 @@ export function App() {
     setChatStore({ ...chatStore });
   };
 
-  // change api key
-  const changAPIKEY = () => {
-    const newAPIKEY = prompt(`Current API KEY: ${chatStore.apiKey}`);
-    if (!newAPIKEY) return;
-    chatStore.apiKey = newAPIKEY;
-    setChatStore({ ...chatStore });
-  };
+  const [showSettings, setShowSettings] = useState(false);
 
   return (
     <div className="flex text-sm h-screen bg-slate-200">
+      <Settings
+        chatStore={chatStore}
+        setChatStore={setChatStore}
+        show={showSettings}
+        setShow={setShowSettings}
+      />
       <div className="flex flex-col h-full p-4 border-r-indigo-500 border-2">
         <div className="grow overflow-scroll">
           <button
@@ -273,10 +249,10 @@ export function App() {
             if (allChatStore.length === 0) {
               allChatStore.push(
                 newChatStore(
-                  defaultAPIKEY() || oldAPIkey,
-                  defaultSysMessage() || oldSystemMessageContent,
-                  defaultAPIEndpoint() || oldAPIEndpoint,
-                  defauleMode() || oldMode
+                  getDefaultParams("api", oldAPIkey),
+                  getDefaultParams("sys", oldSystemMessageContent),
+                  getDefaultParams("api", oldAPIEndpoint),
+                  getDefaultParams("mode", oldMode)
                 )
               );
               setSelectedChatIndex(0);
@@ -290,49 +266,16 @@ export function App() {
         </button>
       </div>
       <div className="grow flex flex-col p-4">
-        <p>
+        <p className="cursor-pointer" onClick={() => setShowSettings(true)}>
           <div>
-            <button
-              className="underline"
-              onClick={() => {
-                const newSysMsgContent = prompt(
-                  "Change system message content"
-                );
-                if (newSysMsgContent === null) return;
-                chatStore.systemMessageContent = newSysMsgContent;
-                setChatStore({ ...chatStore });
-              }}
-            >
+            <button className="underline">
               {chatStore.systemMessageContent.length > 13
                 ? chatStore.systemMessageContent.slice(0, 10) + "..."
                 : chatStore.systemMessageContent}
             </button>{" "}
-            <button className="underline" onClick={changAPIKEY}>
-              KEY
-            </button>{" "}
-            <button
-              className="underline"
-              onClick={() => {
-                const newEndpoint = prompt(
-                  `Enter new API endpoint\n(current: ${chatStore.apiEndpoint})\n(default: ${_defaultAPIEndpoint})`
-                );
-                if (!newEndpoint) return;
-                chatStore.apiEndpoint = newEndpoint;
-                setChatStore({ ...chatStore });
-              }}
-            >
-              ENDPOINT
-            </button>{" "}
-            <button
-              className="underline"
-              onClick={() => {
-                const choice = confirm(
-                  "FETCH 模式单次请求一段完整的对话文本，tokens 数量是准确的。\nSTREAM 模式下可以动态看到生成过程，但只能估算 tokens 数量，token 过多时可能裁剪过多或过少历史消息。\n需要使用 STREAM 模式吗？"
-                );
-                chatStore.streamMode = !!choice;
-                setChatStore({ ...chatStore });
-              }}
-            >
+            <button className="underline">KEY</button>{" "}
+            <button className="underline">ENDPOINT</button>{" "}
+            <button className="underline">
               {chatStore.streamMode ? "STREAM" : "FETCH"}
             </button>
           </div>
diff --git a/src/getDefaultParam.ts b/src/getDefaultParam.ts
new file mode 100644
index 0000000..789bdb7
--- /dev/null
+++ b/src/getDefaultParam.ts
@@ -0,0 +1,18 @@
+function getDefaultParams(param: string, val: string): string;
+function getDefaultParams(param: string, val: number): number;
+function getDefaultParams(param: string, val: boolean): boolean;
+function getDefaultParams(param: any, val: any) {
+  const queryParameters = new URLSearchParams(window.location.search);
+  const get = queryParameters.get(param);
+  if (typeof val === "string") {
+    return get ?? val;
+  } else if (typeof val === "number") {
+    return parseInt(get ?? `${val}`);
+  } else if (typeof val === "boolean") {
+    if (get === "stream") return true;
+    if (get === "fetch") return false;
+    return val;
+  }
+}
+
+export default getDefaultParams;
diff --git a/src/settings.tsx b/src/settings.tsx
new file mode 100644
index 0000000..cea0000
--- /dev/null
+++ b/src/settings.tsx
@@ -0,0 +1,156 @@
+import { StateUpdater } from "preact/hooks";
+import { ChatStore } from "./app";
+
+const Help = (props: { children: any; help: string }) => {
+  return (
+    <div>
+      <button
+        className="absolute"
+        onClick={() => {
+          alert(props.help);
+        }}
+      >
+        ❓
+      </button>
+      <p className="flex justify-between">{props.children}</p>
+    </div>
+  );
+};
+
+const Input = (props: {
+  chatStore: ChatStore;
+  setChatStore: (cs: ChatStore) => void;
+  field: "apiKey" | "systemMessageContent" | "apiEndpoint";
+  help: string;
+}) => {
+  return (
+    <Help help={props.help}>
+      <label className="m-2 p-2">{props.field}</label>
+      <input
+        className="m-2 p-2 border rounded focus w-32 md:w-fit"
+        value={props.chatStore[props.field]}
+        onChange={(event: any) => {
+          props.chatStore[props.field] = event.target.value;
+          props.setChatStore({ ...props.chatStore });
+        }}
+      ></input>
+    </Help>
+  );
+};
+const Number = (props: {
+  chatStore: ChatStore;
+  setChatStore: (cs: ChatStore) => void;
+  field: "totalTokens" | "maxTokens" | "tokenMargin" | "postBeginIndex";
+  readOnly: boolean;
+  help: string;
+}) => {
+  return (
+    <Help help={props.help}>
+      <label className="m-2 p-2">{props.field}</label>
+      <input
+        readOnly={props.readOnly}
+        type="number"
+        className="m-2 p-2 border rounded focus w-28"
+        value={props.chatStore[props.field]}
+        onChange={(event: any) => {
+          console.log("type", typeof event.target.value);
+          let newNumber = parseInt(event.target.value);
+          if (newNumber < 0) newNumber = 0;
+          props.chatStore[props.field] = newNumber;
+          props.setChatStore({ ...props.chatStore });
+        }}
+      ></input>
+    </Help>
+  );
+};
+const Choice = (props: {
+  chatStore: ChatStore;
+  setChatStore: (cs: ChatStore) => void;
+  field: "streamMode";
+  help: string;
+}) => {
+  return (
+    <Help help={props.help}>
+      <label className="m-2 p-2">{props.field}</label>
+      <input
+        type="checkbox"
+        className="m-2 p-2 border rounded focus"
+        checked={props.chatStore[props.field]}
+        onChange={(event: any) => {
+          props.chatStore[props.field] = event.target.checked;
+          props.setChatStore({ ...props.chatStore });
+        }}
+      ></input>
+    </Help>
+  );
+};
+
+export default (props: {
+  chatStore: ChatStore;
+  setChatStore: (cs: ChatStore) => void;
+  show: boolean;
+  setShow: StateUpdater<boolean>;
+}) => {
+  if (!props.show) return <div></div>;
+  return (
+    <div className="overflow-scroll flex justify-center absolute w-screen h-screen bg-black bg-opacity-50 z-10">
+      <div className="m-2 p-2 bg-white rounded-lg h-fit">
+        <h3 className="text-xl">Settings</h3>
+        <hr />
+        <div className="box">
+          <Input
+            field="systemMessageContent"
+            help="系统消息，用于指示ChatGPT的角色和一些前置条件"
+            {...props}
+          />
+          <Input field="apiKey" help="OPEN AI API 密钥" {...props} />
+          <Input
+            field="apiEndpoint"
+            help="API 端点，方便在不支持的地区使用反向代理服务"
+            {...props}
+          />
+          <Choice
+            field="streamMode"
+            help="流模式，使用 stream mode 将可以动态看到生成内容，但无法准确计算 token 数量，在 token 数量过多时可能会裁切过多或过少历史消息"
+            {...props}
+          />
+          <Number
+            field="maxTokens"
+            help="最大 token 数量，这个详情参考 OPENAI API 文档"
+            readOnly={false}
+            {...props}
+          />
+          <Number
+            field="tokenMargin"
+            help="当 totalTokens > maxTokens - tokenMargin 时会触发历史消息裁切，chatgpt会“忘记”一部分对话中的消息（但所有历史消息仍然保存在本地）"
+            readOnly={false}
+            {...props}
+          />
+          <Number
+            field="postBeginIndex"
+            help="指示发送 API 请求时要”忘记“多少历史消息"
+            readOnly={false}
+            {...props}
+          />
+          <Number
+            field="totalTokens"
+            help="token总数，每次对话都会更新此参数，stream模式下该参数为估计值"
+            readOnly={true}
+            {...props}
+          />
+        </div>
+        <hr />
+        <div className="flex justify-end">
+          <button
+            className="p-2 m-2 rounded bg-cyan-600 text-white"
+            onClick={() => {
+              props.setShow(false);
+            }}
+          >
+            Close
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+};