Based on the Joule heating effect of gas discharge in the working process of the plasma actuator, the plasma synthetic jet is simulated with a three-dimensional phenomenological model, under the assumption of local thermodynamic equilibrium plasma.The flow field evolution process of the plasma synthetic jet during a whole cycle is obtained. The results show that in the self-sustained periodical jet built by a single energy deposition, there is a maxium pulse frequency–saturated frequency which could relaize that the cavity is recovered sufficiently. Large energy deposition, small exit orifice diameter and high diameter-height ratio with the same cavity volume could induce higher speed jet, and the increase of the jet speed occurs concurrently with the decrease of the saturated frequency. During a saturated cycle, up to 16% of the mass in the cacity is expelled, but the recovery can only achieve about 90% of the initial mass in the cavity. Plasma synthetic jet actuator is supplied by a capacitive power supply at atmospheric pressure, the fractions of power that go into gas heating and jet kinetic energy are 5% and 1.6% respectively.