In order to extract the mechanical power of the hydraulic pump driven by the aero-engine，the aero-engine hydraulic load system was designed by analyzing the current situation of the aero-engine hydraulic load system,combining with the tested hydraulic pump and the flight test platform.The working principle of the system was described,the heat transfer and pipeline pressure loss calculation,and integrated installation design were carried out.The results of ground debugging and flight test show that the system has high integration degree, good heat transfer effect and good maintainability,which can meet the requirement of extracting the mechanical power from the aero-engine hydraulic pump.