Electric hydrostatic actuator (EHA) will widely used in future aerospace vehicle high-power servo actuator. Considering its multi-disciplinary coupling characteristics, it is necessary to study the structural parameters after the EHA architecture design. Firstly, the Simulink model of EHA was set up.The simulation analysis of system was completed.The influences of motor parameters, hydraulic pump parameters, hydraulic cylinder and load parameters on EHA performance were analyzed. The design efficiency and reliability are improved.