How can i do a handstand push up?

Handstand pushups: That is a great question. Start with v pushups, or pushups with your butt in the air and your weight over your shoulders. You can also do this with your legs up on a chair or stairs, and your hands lower than you. You can eventually tripod against the wall and then progress to kicking your legs up against the wall. Google handstand pushup progression and you will get a flood of crossfit coaches showing you.

A lot of practice: And some strong shoulders. Realize a handstand pushup is really an inverted military press. So unless you can shoulder press your own body weight a handstand push up will be all but impossible. But if you work on your shoulder(deltoid) strength and your balance(though you can always use a wall), this will be a good start.