The contour error produced by the feed system of CNC machine tools has a serious impact on the quality of products.In order to compensate the contour error,an iterative learning contour controller was designed to improve the contour following effect of the feed system.After analyzing the feed system of NC machine tools,the model of tracking error and contour error was obtained.Based on this model,linear interpolation method and circular interpolation method were designed to calculate the size of contour error.Then,through the analysis of the closedloop transfer function of the feed system in s domain,PID feedback compensator was adopted to design the iterative learning contour controller,and the actual contour error was compensated by the controller.Simulation results show that the maximum tracking error generated by the proposed method is 657% when tracking the expected trajectory,which is 57% lower than that of PID method.When tracking the expected contour,the maximum contour error generated is 08 mm,which is 07 mm lower than that of PID method.Therefore,the presented method has a good compensation performance for contour error and can control the contour following accuracy of CNC machine feed system.