With the development of aircraft to multi-electric/all-electric direction, the airborne hydraulic actuating system is changing to high-power electro-hydraulic system. Electro-hydraulic dynamic system adopts integrated high integration design, which has the advantages of strong survivability, good maintainability, high testability and high energy comprehensive utilization ratio. Electro-hydraulic actuating system converts electrical energy from aircraft into hydraulic energy by electric motor driving hydraulic pump, and energy output and actuation are realized by controlling electric motor. In this process, the electric motor, hydraulic pump and actuator all generate a lot of heat. The system only relies on air to heat dissipation, if heat dissipation does not cause the safety of the electro hydraulic system. Therefore, it is necessary to analyze thermal characteristics of the electro-hydraulic system and protect the heat dissipation, so as to realize the temperature control in the safe range of the system. In this paper, based on AMESIM and CFD software, thermal characteristics of electro-hydraulic dynamic system are simulated and calculated.