Hi,
I'm using Linux Mint 16 KDE edition. I also used Mint 16 with Mate desktop environment and never had such issue, so i decided to write it here.
Sometimes when i suspend my computer, it resumes immediately.
How to debug it?
I think it's related to USB, but i'm not certain.
I need to complete guide debugging such situation or just solution.
I use KDE since a few days, and i must say i'm in love

First thing we need to do is determine the exact circumstances which cause your machine to immediately resume.
Possible things triggering it include the opening/closing of the lid, wired network connections, or the connection of certain peripherals (particularly via USB as you noted earlier).