Abstract: In order to investigate the influences of the high-voltage electrode shape on the annular surface dielectric barrier discharge characteristics and aerodynamic excitation, a sawtooth annular actuator was designed in this paper, and the influences of sawtooth number on current waveforms, discharge images, discharge power, thrust and flow field under alternating current power were investigated. The research results show that the number of current pulses during the voltage rise period increases after increasing the sawtooth, which is related to the electric field distribution of sawtooth and the increase of exposed electrode length. The average power and voltage have an approximately linear relationship and the average power decreases gradually as the number of sawtooth increases. The existence of sawtooth results in the concentration of discharge channels at the inner edge of the electrode, and the relatively dense sawtooth structure design helps to improve the uniformity of discharge. The sawtooth annular surface dielectric barrier discharge produces a larger area of plasma at lower power, and the symmetry of the plasma distribution reaches the best when the number of sawtooth is equal to 12. The cancellation effect of the external electric fields of adjacent sawtooth results in the suppression of micro-discharge formation. The external electric field distribution determines the growth of the discharge area. The sawtooth structure increases the thrust and thrust-to-power ratio of the annular actuator. The increase in thrust is related to the number of current pulses and the average power. The horizontal distribution of the flow field gradually narrows as the number of sawtooth increases, and the momentum generated by the discharge is more concentrated in the vertical direction.