The widely-used Constant Power Loads (CPL) have a crucial impact on the stability of the aircraft power system.The characteristics of CPL are analyzed,and an equivalent circuit model of the High-Voltage DC (HVDC) power system of More Electric Aircraft (MEA) is established.Based on the small-signal analysis method,the effects of CPL variation on the stability of the system are studied.It is concluded that an increasing CPL will reduce the system′s stability,and the capacitive loads in parallel can slow this trend.In order to protect the system,a reference voltage controller is designed,which can reduce the current in the load line and compensate for the load voltage when the system is under heavy load.Based on the Simulink platform,a time-domain simulation model is established.Simulation results have proved the correctness of stability analysis and the effectiveness of the designed controller.