Hello Neha,To get admission into IIT through GATE for any of the MTECH courses,there are some educational qualifications:

• The candidate must have a minimum CPI of 6.5 or 60% of marks or First Cass in the qualifying degree.
• All regular category candidates (except those having BTech degrees from an IIT with a minimum CPI of 7.0) must possess a valid score of Graduate Aptitude Test in Engineering (GATE). 
• The Minimum experience required for Sponsored (Full-time) and Part-Time categories of candidates, have been given in the link below.

There are some other qualifications required to admission in the courses and to know them,go through the link given below.

http://www.iitg.ac.in/acad/EligibilityCriteria/ECMTechMDes.htm

Best of luck!!