In order to improve the efficiency and accuracy of mechanical parameter identification of feed system,a method of mechanical parameter identification for double inertia feed system was proposed based on double excitation signal.The pseudorandom binary signal was used to identify the mechanical transmission link in frequency domain.According to the frequency response characteristics of the system,the sweep signal frequency band was designed.The least square method of ARMAX model was used to estimate the discrete structure and disturbance of the dual inertia dynamic model,the discrete transfer function was transformed into the continuous time transfer function by the zero pole matching method,and the mechanical parameters of the system were solved.In order to reduce the influence of nonlinear friction,the whole experiment was carried out in acceleration.The fitting degree between the final model output and the actual output is 9861%,and the residual analysis meets the theoretical performance verification index,which improves the accuracy and efficiency of the mechanical parameter identification for dual inertia feed system.