To drive servovalve driven by giant magnetostrictive actuator,a new type of servo amplifier for servovalve driven by giant magnetostrictive actuator has been designed and the circuit model has been established by considering the specification requirements for the driving power of giant magnetostrictive actuator and the servo amplifier using in servovalve.The effect of the open loop gain of power operational amplifier on its output performance has been simulated and analyzed.The simulation results show that the circuit characteristic can meet the requirements when the open loop gain of power operational amplifier is more than 80 dB.When the driving load is a rated value,the measured results of the prototype are that the linearity of the output current is 3%,the adjusting time of step response is less than 0.5 ms and the amplitude frequency bandwidth is 2 kHz at 2 A of output current. When the driving frequency is less than 1 kHz,the distortion of output current is small and no phase lagging.