Abstract: A method to reduce the ripple errors is proposed by analyzing the generation of medium and high frequency errors. To break the regular distribution of the path, a random disturbance is added to the stepping direction of the grating path, and the errors of a specific frequency are effectively suppressed.The random path is analyzed based on the principle of information entropy, and it is concluded that the disturbance amplitude is the key factor to reduce the ripple errors.On this basis, the generated random perturbation path is smoothed and optimized to reduce the dynamic performance requirements of machine tools. The simulation results show that the optimized path can reduce the surface ripple errors effectively.