Based on the weapon bay door of a certain type of UAVas a loading object,in order to meet requirements of the UAV restrictions on the weight and size, to achieve rapid and large angleof the door opening and closing movement, closed circuit and open circuitoftwo rotary electrohydrostatic actuator of schemes were designed.Through analyzing the working principle and the element parameter calculation of two kinds of schemes, the open circuit system of rotary electrohydrostatic actuator had a great superiority in the motor power, pump delivery and system heating power.By using AMESim simulation platform, the designed rotary electrohydrostatic actuatorwas simulated in movement. The performance of actual system was well reflected by the simulation model. The simulation results show that thescheme of open circuit hydraulic system has advantages infast response speed and short adjusting time, which satisfied the requirements in design. 