截取自：https://blog.csdn.net/aerchi/article/details/85612123
You can access the list of Environment Variables present in your computer using System properties -> Advanced -> Environment Variables button. You can also directly access it using control sysdm.cpl,system,3 command in RUN dialog box.
Windows XP Environment Variables
| Environment Variable | Path |
|---|---|
| %ALLUSERSPROFILE% | C:\Documents and Settings\All Users |
| %APPDATA% | C:\Documents and Settings\Username\Application Data |
| %COMMONPROGRAMFILES% | C:\Program Files\Common Files |
| %COMMONPROGRAMFILES(x86)% | C:\Program Files (x86)\Common Files |
| %COMSPEC% | C:\Windows\System32\cmd.exe |
| %HOMEDRIVE% | C: |
| %HOMEPATH% | C:\Documents and Settings\Username |
| %PROGRAMFILES% | C:\Program Files |
| %PROGRAMFILES(X86)% | C:\Program Files (x86) (only in 64-bit version) |
| %SystemDrive% | C: |
| %SystemRoot% | C:\Windows |
| %TEMP% and %TMP% | C:\Documents and Settings\Username\Local Settings\Temp |
| %USERPROFILE% | C:\Documents and Settings\Username |
| %WINDIR% | C:\Windows |
Windows Vista, Windows 7, Windows 8/8.1 and Windows 10
| Environment Variable | Path |
|---|---|
| %ALLUSERSPROFILE% | C:\ProgramData |
| %APPDATA% | C:\Users\Username\AppData\Roaming |
| %COMMONPROGRAMFILES% | C:\Program Files\Common Files |
| %COMMONPROGRAMFILES(x86)% | C:\Program Files (x86)\Common Files |
| %COMSPEC% | C:\Windows\System32\cmd.exe |
| %HOMEDRIVE% | C: |
| %HOMEPATH% | C:\Users\Username |
| %LOCALAPPDATA% | C:\Users\Username\AppData\Local |
| %PROGRAMDATA% | C:\ProgramData |
| %PROGRAMFILES% | C:\Program Files |
| %PROGRAMFILES(X86)% | C:\Program Files (x86) (only in 64-bit version) |
| %PUBLIC% | C:\Users\Public |
| %SystemDrive% | C: |
| %SystemRoot% | C:\Windows |
| %TEMP% and %TMP% | C:\Users\Username\AppData\Local\Temp |
| %USERPROFILE% | C:\Users\Username |
| %WINDIR% | C:\Windows |
NOTE: Here C: is the system drive where Windows is installed in your system. It might differ for you if you installed Windows in a different drive in your system.