I try to copy some file to /usr/share folder, but the terminal said that operation not permitted even I do the with sudo.  

`sudo cp ~/Downloads/kellys.vim /usr/share/vim/vim73/colors/`  

the result  

`cp: /usr/share/vim/vim73/colors/kellys.vim: Operation not permitted`  

When I try to change the permission of this folder, it came with the same problem. 
I run EI Capitan on Mac. 
I have google it for a long time,but still confused.
How do I solve the problem ?