Numerical simulations of the synthetic jet actuator adopted are carried out for analyzing the influence of rudder deflection angle on airfoil lift characteristics in detail, under 3°~20° rudder deflection angles, one and two synthetic jet actuators. By comparing the lift performance corresponding to the synthetic jet actuator and the cases without synthetic jet actuator, within the scope of this study, the application of synthetic jet actuator can improve the lift coefficient. For a single synthetic jet actuator, effectively improvement of the lift coefficient occurs, but the lift coefficient curve fluctuates with time. When two actuators are used, different combinations of synthetic jet actuators have different promotion effects on the lift coefficient. When the phase difference of two synthetic jet actuators is 0 or π/2, the fluctuation range of the lift coefficient behave a certain degree of reduction. Due to the controllability of the synthetic jet actuator, the synthetic jet actuator is more advisable in certain conditions to achieve better lift characteristics.