iam a diploma student it is very hard to qualify jee mains compare to intermediate but through jee mains we dont have seats .we must write

Hello there
You can get admission through JEE MAINS after diploma but that gets reduced to a limited no. Of courses in a few govt. institutes.
For instance you can apply for some courses at Delhi Technological University(DTU) as it offers some seats to the diploma offers though at times they also need you to have work experience with a diploma.
For more information, you can visit their site.
Good Luck