除了在php.ini中开起扩展之外，还需要复制

• 
  icudt36.dll
  


• 
  icuin36.dll
  


• 
  icuio36.dll
  


• 
  icule36.dll
  


• 
  iculx36.dll
  


• 
  icutu36.dll
  


• 
  icuuc36.dll
  

这些文件到apache的bin目录，或者你的Path变量目录下。

原文为：

For the php_intl.dll extension to work correctly, you need to have the following files in a folder in your PATH:

• 
  icudt36.dll
  


• 
  icuin36.dll
  


• 
  icuio36.dll
  


• 
  icule36.dll
  


• 
  iculx36.dll
  


• 
  icutu36.dll
  


• 
  icuuc36.dll
  

By default they're sitting in your PHP directory, but that directory isn't necessarily in your PATH (it wasn't for me, using xampp)

注意有些版本的xampp里面没有这些文件，PHP官方的包里是有的。