Nozzle-flapper type electro-hydraulic servo valve operated by torque motor has been widely used in industrial applications. As their bandwidths are limited, they are not suitable for high-speed applications. This paper presents a novel nozzle flapper valve driven by the giant magnetostrictive actuator, which has been designed and integrated into the four-nozzle flapper valve to replace the torque motor. And the influence of involved structural parameters on the dynamics of the actuator and the nozzle flapper valve is analyzed by AMESim. The simulation results can provide an important reference and basis for the optimization and design of the four-nozzle flapper valve.