Ram air turbine (RAT) is an emergency power equipment of aircraft，which provides emergency power for aircraft under the action of relative airflow.In order to study the starting performance,dynamic speed regulation performance and emergency power output characteristic of hydraulic RAT,the principle of hydraulic RAT was analyzed,the dynamic model and hydraulic simulation model were established based on Motion and AMESim.By creating the interface file,the co-simulation model of hydraulic RAT was established,and dynamic and hydraulic co-simulation was realized.The simulation results are consistent with the theoretical analysis results,which verifies the feasibility of the co-simulation method and provides a method for the design and analysis of hydraulic RAT.