In order to study the mechanism of dielectric barrier surface discharge（DBDs）

the discharge process is simulated which is excited by sine voltage.The variation of electron density

ion density

electric field

discharge current and body force with time are gained.The discharge models of plasma discharge start process are fake glow-glow-filamentary discharge by analyzing current characteristics.The asymmetry of electron avalanche

electric field intensity and body force is the essential reason of unidirectional body force excited by sine voltage."Push-pull"is the plasma flow control mechanism

and that higher induced velocity is due to the particle inertial delay.At last

an optimized preparatory voltage wave is presented.