Rudder transmission system is composed of electro-mechanical actuator (EMA),transmission mechanism,rudder surface and controller in all/more electric aircraft,which can directly influence the flight control effects and flight quality of aircrafts.According to the structure composition of the electro-mechanical actuator (EMA),the system dynamics equations were established,and the dynamic model was established based on the AMESim software through graphical modeling.Based on Virtual.Lab Motion software,the model of the transmission mechanism was established,which considered the influence of nonlinear contact collision effect with gaps,elastic deformation of components and rudder surface load.Based on the Coupled co-simulation method,the co-simulation model of the rudder transmission system was established.The experiments of sine-input were made in comprehensive performance test bench,and the experimental results were compared with the co-simulation ones.The results show that the error between simulation results and experimental results is small,which verifies the effectiveness of the co-simulation model.