I want to make particle system have gravity,so what should i do? I tried to add RIGID BODY type dynamic,but useless.

A particles position is determined by the velocity graphs in the particle system component. To make a particle behaviour like it is under gravity you should give the particle a Y velocity that goes down in a straight line. Like this:

HI dave,thank you for your time.I use this way at now,but have a problem that i donβt know how much should be set for slope of this line.

I want to acceleration of particle equal acceleration of gravity.

thanks.

Acceleration due to gravity is approx. 10 m/s/s so you can work out how much to change the velocity depending on the lifetime of the particle.

If the lifetime of the particle is 3 seconds, the x - axis of the graph is 0-3 seconds. Over 3 seconds a free falling particle will change velocity by 30 m/s ( accel * delta-t, 10 * 3) so you should have the end point 30 below the start point.

Hope that makes sense?

Thank you very much,i has been successfully resolved this problem.