The performances of pulsed jet on-off valve based on giant magnetostrictive actuator(GMA) are affected by structure parameters of actuator. The physical model between flux and driving current of the valve was built，and their relationship was simulated by Matlab. The response of different parameters, such as number of solenoids, eddy current time constant, effective mass of actuator, effect on the valve flux in frequency domain and time domain were analyzed respectively. The trends of flux with actuator parameters were abstracted from the simulation results. The eddy current time constant was the main factor which confirmed by experiments. To enlarge the response frequency band and shorten the response time, the number of the solenoid and the eddy current time constant should be decreased