diff --git a/README.md b/README.md
index 73fbe62..872e5ef 100644
--- a/README.md
+++ b/README.md
@@ -74,6 +74,7 @@ This library contains all the reference documentation and API reference-related
 	* [Bytes](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/bytes.md)
 	* [File](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/file.md)
 	* [Dir](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/dir.md)
+	* [Environmental Variables](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/env.md)
 	* [Threading](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/thread.md)
 	* [Networking](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/net.md) @kjessup
 	* [OAuth2 and Providers](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide/OAuth2.md)
diff --git a/README.zh_CN.md b/README.zh_CN.md
index c8f3124..7fb6f96 100644
--- a/README.zh_CN.md
+++ b/README.zh_CN.md
@@ -90,6 +90,7 @@
 	* [字节流转换](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/bytes.md)
 	* [文件操作](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/file.md)
 	* [目录与路径](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/dir.md)
+	* [环境变量](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/env.md)
 	* [线程](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/thread.md)
 	* [网络](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/net.md) @kjessup
 	* [OAuth2 身份授权](https://github.com/PerfectlySoft/PerfectDocs/blob/master/guide.zh_CN/OAuth2.md)
diff --git a/guide.zh_CN/env.md b/guide.zh_CN/env.md
new file mode 100644
index 0000000..b6b8b38
--- /dev/null
+++ b/guide.zh_CN/env.md
@@ -0,0 +1,64 @@
+# 环境变量
+
+## 使用方法
+
+首先导入PerfectLib：
+
+``` swift
+import PerfectLib
+```
+
+现在可以在程序中直接调用`Env`类对象操作环境变量：
+
+### 设置
+
+- 设置一个环境变量
+
+以下操作等同于 bash 命令 "export foo=bar"
+
+``` swift
+Env.set("foo", value: "bar")
+```
+
+- 设置一组环境变量
+
+同样可以使用字典方式设置一组环境变量
+
+``` swift
+Env.set(["foo":"bar", "koo":"kar"])
+// 结果等同于 bash 命令 "export foo=bar && export koo=kar"
+```
+
+### 读取
+
+- 查询单个变量：
+	
+``` swift
+guard let foo = Env.get("foo") else {
+	// 查询失败
+}
+```
+
+- 查询单个变量，并附加默认值（如果不存在这个变量就用默认值代替）
+
+``` swift
+guard let foo = Env.get("foo", defaultValue: "bar") else {
+	// 既然有默认值，则查询应该不会失败
+}
+```
+
+- 查询所有系统变量
+
+``` swift
+let all = Env.get()
+// 结果是一个字典 [String: String]
+```
+
+### 删除
+
+- 删除一个环境变量:
+
+
+``` swift
+Env.del("foo")
+```
\ No newline at end of file
diff --git a/guide.zh_CN/toc.json b/guide.zh_CN/toc.json
index 444ce27..e758493 100644
--- a/guide.zh_CN/toc.json
+++ b/guide.zh_CN/toc.json
@@ -136,6 +136,10 @@
 					"name": "目录与路径",
 					"doc":  "dir"
 				},
+				{
+					"name": "环境变量",
+					"doc":  "env"
+				},
 				{
 					"name": "文件操作",
 					"doc":  "file"
diff --git a/guide/env.md b/guide/env.md
new file mode 100644
index 0000000..75a374d
--- /dev/null
+++ b/guide/env.md
@@ -0,0 +1,63 @@
+# Environmental Operations
+
+## Usage
+
+First, ensure the `PerfectLib` is imported in your Swift file:
+
+``` swift
+import PerfectLib
+```
+You are now able to use the `Env` class to operate the environmental variables
+
+### Set
+
+- Single Variable Setting:
+
+This statement is equal to bash command "export foo=bar"
+
+``` swift
+Env.set("foo", value: "bar")
+```
+
+- Group Setting:
+
+It is also possible to set a group of variables in a dictionary style:
+
+``` swift
+Env.set(["foo":"bar", "koo":"kar"])
+// the result is identically the same as "export foo=bar && export koo=kar"
+```
+
+### Get
+
+- Single variable query:
+	
+``` swift
+guard let foo = Env.get("foo") else {
+	// there is no such a variable
+}
+```
+
+- Single variable query with a default value:
+
+``` swift
+guard let foo = Env.get("foo", defaultValue: "bar") else {
+	// there is no such a variable even with a default value??
+}
+```
+
+- Query all system variables:
+
+``` swift
+let all = Env.get()
+// the result of all is a dictionary [String: String]
+```
+
+### Delete
+
+- Delete an environmental variable:
+
+
+``` swift
+Env.del("foo")
+```
\ No newline at end of file
diff --git a/guide/toc.json b/guide/toc.json
index 40228a6..39d0e03 100644
--- a/guide/toc.json
+++ b/guide/toc.json
@@ -136,6 +136,10 @@
 					"name": "Dir",
 					"doc":  "dir"
 				},
+				{
+					"name": "Environmental Variables",
+					"doc":  "env"
+				},
 				{
 					"name": "File",
 					"doc":  "file"