Abstract: In order to carry out the experimental research on active control of separated flow over airfoils, two forms of synthetic jet actuators based on piezoelectric vibration diaphragm were designed.The hot wire anemometer measurements were performed on synthetic jets with rectangular orifice in quiescent environment.The results indicate that the vertical synthetic jets can obtain a maximum speed of 21.32 m/s.The airfoil separation active control experiment based on synthetic jet technology was performed in two-dimensional testing section of NF-3 wind tunnel, the inclined synthetic jets in the airfoil experiment can obtain 10 m/s order magnitude speed, postpone the airfoil surface flow separation and improve the airfoil stall's characteristic.When the synthetic jet actuator is working, airfoil maximum lift coefficient can increase by 11.36% and the angle of attack stall can increase by 3°.At the same time, it's observed that the effect of active control on flow separation is effective when momentum coefficient reaches the order of magnitude of 10-3, and there will be no effect if the momentum coefficient is less than the order of magnitude of 10-4.