To get qualified in KIITEE, you must have passed your 10th and 12th board completely. You need to have scored a minimum 60% marks in Mathematics, Physics and Chemistry in order to be qualified. Anyways, you can know the cutoff rank for the various respective branches offered by the institute, but the institute never displays the marks of the candidates appearing in the KIITEE exam, so estimating the exact marks and cutoff is quite difficult. So, just set your target only on the entrance exam and prepare accordingly and do well.
The link given below will help you to know regarding the cutoff rank in getting into KIIT.
Hope, it helps you.