Abstract: Aviation vector nozzle actuators are seriously affected by the heat radiation of the engine, thus, the oil return cooling method is often used to control the temperature of the actuator components. Considering the convection and radiation between the engine and the servo valve actuator, and the heat transfer process of each component of the actuator, a thermodynamic model of the vector nozzle actuator was established based on the lumped parameter method under real working conditions. The model was used to analyze and obtain the temperature distribution law and its influencing factors of each component of the actuator during the piston in neutral position and reciprocate. The analysis results show that when the piston is in near the neutral position, the oil flow passes the cooling channel, taking away heat through heat conduction, getting better cooling effect. When the piston reciprocates, the oil continuously enters and exits the rod cavity and the rodless cavity, and the temperature of each node can reach a stable fluctuation state and be lower than the thermal equilibrium temperature of the neutral position. The temperature of each node of the actuator increases with the increase of the radiation temperature, ambient temperature and oil temperature, among which the radiation temperature of the engine brake has the most obvious influence. The cylinder barrel is directly affected by the thermal radiation of the brake. When the temperature of the brake rises from 300 °C to 400 °C, the temperature of the cylinder barrel on the left and right sides can increase by about 40 °C. Through convective heat transfer, the temperature of each node of the actuator can increase linearly with the increase of ambient temperature and oil temperature.