According to the reliability requirement of modern weapon system, dual CPU redundant control technique is proposed. The principle of electro hydraulic servo system is briefly introduced, and the specific implementation methods of hardware system and software system based on dual CPU redundancy control are described in detail. The failure detection module and the non disturbance switching module are focused on analysis and analyzed the semi physical simulation. Simulation results show that the method can effectively improve the reliability of the system and realize the non disturbance switching of the system, which has certain application value.