after lot of googling i got below
& its really doing great job
So lets get started!
1. Login to your server and su to root, I know the irony!
2. cd /root
3. pico .bashrc
4. Scroll to the end of the file then add the following:
echo 'ALERT - Root Shell Access (YourserverName) on:' `date` `who` | mail -s "Alert: Root Access from `who | cut -d"(" -f2 | cut -d")" -f1`" email@example.com
Replace YourServerName with the handle for your actual server
Replace firstname.lastname@example.org with your actual email address
5. Crtl + X then Y
Now logout of SSH, close the connection and log back in! You should receive an email address of the root login alert a few minutes afterwards.