方法一：
1、点击Windows+R组合键键，键入regedit，然后按Enter键;
2、在左侧依次展开HKEY_CURRENT_USER \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ Explorer，右键选择【新建】-【项】，将该名称命名为MultitaskingView;
3、右键单击MultitaskingView，然后选择【新建】-【项】，将该项命名为AltTabViewHost;
4、右键单击AltTabViewHost，然后选择新建》 Dword(32位)值，命名为：Grid_backgroundPercent ;
5、双击打开Grid_backgroundPercent，输入需要设置的透明度(以百分比设置值。 0表示100%透明度，100%无透明度。);
6、在AltTabViewHost上单击右键，然后选择新建》 Dword(32位)值，将其命名为BackgroundDimmingLayer_percent，以百分比设置值，100%为完全调光。
方法二：
1、直接将下面代码复制到记事本中;
01Windows Registry Editor Version 5.00
02; Set transparency of Alt-Tab interface between 00000000 (full transparency) and 000000100 (no transparency)
03[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MultitaskingView\AltTabViewHost]
04"Grid_backgroundPercent"=dword:00000100
05; Set whether windows are shown behind the Alt-Tab interface. 00000000 is no, 00000001 is yes
06[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MultitaskingView\AltTabViewHost]
07"Wallpaper"=dword:00000001
08; Sets the dim percentage of the background, 00000000 is no dimming, 00000100 is full dimming
09[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MultitaskingView\AltTabViewHost]
10"BackgroundDimmingLayer_percent"=dword:000000100
复制代码
Windows Registry Editor Version 5.00; Set transparency of Alt-Tab interface between 00000000 (full transparency) and 000000100 (no transparency)[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MultitaskingView\AltTabViewHost]"Grid_backgroundPercent"=dword:00000100; Set whether windows are shown behind the Alt-Tab interface. 00000000 is no, 00000001 is yes[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MultitaskingView\AltTabViewHost]"Wallpaper"=dword:00000001; Sets the dim percentage of the background, 00000000 is no dimming, 00000100 is full dimming[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MultitaskingView\AltTabViewHost]"BackgroundDimmingLayer_percent"=dword:000000100
2、点击记事本左上角的“文件”，在下拉菜单中选择“另存为”;
3、在打开的另存为窗口，先点击窗口左侧的“桌面”，然后在在文件名(N)栏中输入“Alt-Tab界面边框透明度.reg ”，再点击“保存”;
4、双击Alt-Tab界面边框的透明度.reg文件 ，导入注册表即可。