An Internal Model Control (IMC) method is proposed for electronic-hydraulic servo system in this paper.As an advanced control algorithm,the design idea of IMC is that the object model is connected to the actual object in parallel,and the controller approaches the dynamic inverse of the model.Considering the advantages of IMC such as being insensitive to the model error,the electronic-hydraulic servo system model is simplified by reducing orders.The controller based on the simplified model has only one adjustable parameter which is directly related to system dynamic performance and robustness.Therefore,the parameter is regulated conveniently,and the randomicity and complexity of the controller regulation are avoided.Simulation and experiment results show that the IMC method overcomes parameter perturbation and improves the tracking performance and robustness of system.Furthermore,the artillery tracking error is within ±0.36 mrad.