how to set umask to 0000 for a specail user?
 

Please see below:
vim ~/.bashrc
umask=0000(bottom line)
source ~/.bashrc

But when I relogin, default umask was still 0022.

How could I do ?

'umask=0000' sets an environment variable called 'umask' to '0000'. It does not set your umask. To do that, you need to call the 'umask' command with '0000' as a parameter'. Thus, 'umask 0000'.