if you mean have a different php.ini file for each site, the answer is no. You could include a page that uses some ini_set()ers for each site and accomplish the same thing however.
but there are many hosts that i see their users can put their php.ini (with some of directives) in their folders, and it'll be executed as directive ini. how is that?
I think it has to do with virtual dedicated servers. Individual hosted accounts typical use the servers php.ini version. I could be way off here though.