diff --git a/README.md b/README.md
index 115e97a..796073a 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,15 @@ developers apply FSRS to their flashcard applications, there by improving the us
 npm install ts-fsrs
 ```
 
+# Environment Variables
+If you need to customize default parameters, you can modify the values using `.env`/`.env.local`/`.env.production`/`.env.development`.
+
+Copy the [.env.local.example](./example/.env.local.example) file in this directory to .env.local (which will be ignored by Git):
+
+```bash
+cp .env.local.example .env.local
+```
+
 # Example
 
 ```typescript
diff --git a/example/.env.local.example b/example/.env.local.example
new file mode 100644
index 0000000..13bfc3b
--- /dev/null
+++ b/example/.env.local.example
@@ -0,0 +1,6 @@
+FSRS_REQUEST_RETENTION=0.8
+FSRS_MAXIMUM_INTERVAL=36500
+FSRS_EASY_BOUND=1.3
+FSRS_HARD_FACTOR=1.2
+FSRS_W='[1, 1, 5, -0.5, -0.5, 0.2, 1.4, -0.12, 0.8, 2, -0.2, 0.2, 1]'
+FSRS_ENABLE_FUZZ=true
\ No newline at end of file
diff --git a/example/index.ts b/example/index.ts
index 4d0f37e..21fa709 100644
--- a/example/index.ts
+++ b/example/index.ts
@@ -1,5 +1,5 @@
 import {
-    fsrs, int,
+    fsrs, FSRSVersion, generatorParameters, int,
     Rating,
     State
 } from 'ts-fsrs';
@@ -53,4 +53,6 @@ const test = () => {
     generatorExample4().forEach(item => print_scheduling_card(item));
 }
 
+console.log(`FSRSVersion:${FSRSVersion}`)
+console.log('defaultParams',generatorParameters())
 test()
\ No newline at end of file
diff --git a/package.json b/package.json
index e6da2ba..d8c1403 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ts-fsrs",
-  "version": "2.1.1",
+  "version": "2.2.0",
   "description": "ts-fsrs is a TypeScript package used to implement the Free Spaced Repetition Scheduler (FSRS) algorithm. It helps developers apply FSRS to their flashcard applications, thereby improving the user learning experience.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -10,11 +10,12 @@
     "FSRS"
   ],
   "dependencies": {
+    "dotenv": "^16.3.1",
     "seedrandom": "^3.0.5"
   },
   "devDependencies": {
-    "@types/node": "^20.6.2",
     "@types/jest": "^29.5.5",
+    "@types/node": "^20.6.2",
     "@types/seedrandom": "^3.0.5",
     "@typescript-eslint/eslint-plugin": "^6.7.0",
     "@typescript-eslint/parser": "^6.7.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 5f9aabf..35acd98 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -5,6 +5,9 @@ settings:
   excludeLinksFromLockfile: false
 
 dependencies:
+  dotenv:
+    specifier: ^16.3.1
+    version: 16.3.1
   seedrandom:
     specifier: ^3.0.5
     version: 3.0.5
@@ -1390,6 +1393,11 @@ packages:
       esutils: 2.0.3
     dev: true
 
+  /dotenv@16.3.1:
+    resolution: {integrity: sha512-IPzF4w4/Rd94bA9imS68tZBaYyBWSCE47V1RGuMrB94iyTOIEwRmVL2x/4An+6mETpLrKJ5hQkB8W4kFAadeIQ==}
+    engines: {node: '>=12'}
+    dev: false
+
   /electron-to-chromium@1.4.523:
     resolution: {integrity: sha512-9AreocSUWnzNtvLcbpng6N+GkXnCcBR80IQkxRC9Dfdyg4gaWNUPBujAHUpKkiUkoSoR9UlhA4zD/IgBklmhzg==}
     dev: true
diff --git a/src/fsrs/default.ts b/src/fsrs/default.ts
index 2723a0e..518a218 100644
--- a/src/fsrs/default.ts
+++ b/src/fsrs/default.ts
@@ -1,15 +1,41 @@
 import { Card, FSRSParameters, State, FSRS } from "./index";
+import dotenv from "dotenv";
+import { EnvParams } from "./type";
 
-export const default_request_retention = 0.9;
-export const default_maximum_interval = 36500;
-export const default_easy_bonus = 1.3;
-export const default_hard_factor = 1.2;
-export const default_w = [
+dotenv.config({ path: `./.env.local` });
+dotenv.config({ path: `./.env.production` });
+dotenv.config({ path: `./.env.` });
+dotenv.config({ path: `./.env.development` });
+
+export const envParams: EnvParams = {
+  FSRS_REQUEST_RETENTION: Number(process.env.FSRS_REQUEST_RETENTION),
+  FSRS_MAXIMUM_INTERVAL: Number(process.env.FSRS_MAXIMUM_INTERVAL),
+  FSRS_EASY_BOUND: Number(process.env.FSRS_EASY_BOUND),
+  FSRS_HARD_FACTOR: Number(process.env.FSRS_HARD_FACTOR),
+  FSRS_W: process.env.FSRS_W
+    ? JSON.parse(process.env.FSRS_W as string)
+    : undefined,
+  FSRS_ENABLE_FUZZ: Boolean(process.env.FSRS_ENABLE_FUZZ),
+};
+
+export const default_request_retention = !isNaN(envParams.FSRS_REQUEST_RETENTION)
+  ? envParams.FSRS_REQUEST_RETENTION
+  : 0.9;
+export const default_maximum_interval = !isNaN(envParams.FSRS_MAXIMUM_INTERVAL)
+  ? envParams.FSRS_MAXIMUM_INTERVAL
+  : 36500;
+export const default_easy_bonus = !isNaN(envParams.FSRS_EASY_BOUND)
+  ? envParams.FSRS_EASY_BOUND
+  : 1.3;
+export const default_hard_factor = !isNaN(envParams.FSRS_HARD_FACTOR)
+  ? envParams.FSRS_HARD_FACTOR
+  : 1.2;
+export const default_w = envParams.FSRS_W || [
   1, 1, 5, -0.5, -0.5, 0.2, 1.4, -0.12, 0.8, 2, -0.2, 0.2, 1,
 ];
-export const default_enable_fuzz = false;
+export const default_enable_fuzz = envParams.FSRS_ENABLE_FUZZ || false;
 
-export const FSRSVersion: string = "2.1.1";
+export const FSRSVersion: string = "2.2.0";
 
 export const generatorParameters = (props?: Partial<FSRSParameters>) => {
   return {
diff --git a/src/fsrs/index.ts b/src/fsrs/index.ts
index 17c6843..facdd19 100644
--- a/src/fsrs/index.ts
+++ b/src/fsrs/index.ts
@@ -10,6 +10,7 @@ export {
   generatorParameters,
   createEmptyCard,
   fsrs,
+  envParams
 } from "./default";
 export {
   date_scheduler,
diff --git a/src/fsrs/type.ts b/src/fsrs/type.ts
index dcd24cb..cbba460 100644
--- a/src/fsrs/type.ts
+++ b/src/fsrs/type.ts
@@ -1,3 +1,12 @@
 export type unit = "days" | "minutes";
 export type int = number & { __int__: void };
-export type double = number & { __double__: void };
\ No newline at end of file
+export type double = number & { __double__: void };
+
+export interface EnvParams{
+    FSRS_REQUEST_RETENTION:number,
+    FSRS_MAXIMUM_INTERVAL:number,
+    FSRS_EASY_BOUND:number,
+    FSRS_HARD_FACTOR:number,
+    FSRS_W?:number[],
+    FSRS_ENABLE_FUZZ?:boolean
+}
\ No newline at end of file