With the background of the development of Aircraft Anti-skid Braking System, a new aircraft Electro-Hydrostatic Actuator (EHA) of a certain model fighter was designed to meet the need of the braking system. The paper described the principle of work and features of the EHA, gave the specific requirements of the system. The selection and performance of the motor, pump and hydraulic cylinder were optimized. Then, the paper described the principle of work and features of the EHA, modeled and simulated it with MATLAB/Simulink., and analyzed the effects of all structural parameters on the performance. The results of EHA reached the design target of dynamic performance. Finally, the whole model of the aircraft system was built and established based on the EHA model and results. The results of the dry runway condition verified the correctness of the EHA design, so the Hydro Actuator of traditional aircraft anti-skid braking system could be replaced by EHA.