An intelligent design method of EHA was proposed to realize the main parameter design,optimization design,database system and 3D modeling functions.Based on the design method and process of electro-hydrostatic actuator(EHA),12 main design parameters were obtained.The design method of EHA intelligent design knowledge base was proposed to complete the design of rule system,knowledge system and model base.By inputting the size of installation space,using NSGA-II genetic algorithm and optimizing the target including space volume and mechanical performance,the layout and structure of each part of EHA were obtained.Furthermore,the data storage and recall were realized for each part parameter.The intelligent design of EHA is completed with less input parameters,which improves the efficiency of designers and shortens the R & D cycle.