Ramjet air turbine （RAT） can provide the electrical and hydraulic power needed in an emergency to keep the aircraft safe. The key to ensure the safety of aircraft is whether the RAT system can release energy smoothly within the specified time. The releasing speed is mainly controlled by the damping hole of the actuator cylinder， but there is a lack of research on the design of the damping hole of RAT actuator cylinder in China. Therefore， the design of damping hole of actuator cylinder in RAT system is studied by using simulation technology. First， according to the structure and working principle of the RAT actuator， the RAT actuator model is established by using AMESim， and its correctness is verified. AMESim is a model and a simulation platform based on physical model， which includes hydraulic component design library， power transmission library， etc. It is widely used in modeling and simulating of hydraulic systems. Then， through the simulation experiment， the effect of damping hole design on RAT releasing time is studied. Finally， for the RAT releasing time requirements（0.6—0.8 s） of regional aircraft and small aircraft， the optimal design of damping holes is carried out， which provides support for the design of damping holes of RAT actuators.