Am I eligible for H1b Masters cap in april 2017? I am getting my Masters degree april 2017?

I am graduating in April 2017. My employer wants to apply for H1b in April 2017.

Am I eligible for masters quota on the base of my masters degree that is getting completed in april 2017.

No, you will not be. You need to have the degree completed and attach a copy of your transcript+ degree certificate with your application. If you graduate in April 2017, I believe you wont have these with you on Apr 1st.