According to the accuracy requirements of aspheric components in the optical systems, the linear grating polishing trajectory of magnetic compound fluid polishing is designed to polish aspheric compoents. Based on the polishing trajectory and the aspheric equation, the coordinates of each polishing processing point are calculated. The coordinates of the center point of the polishing head are calculated according to each polishing point and the polishing head which is relative to the geometry of the workpiece. The model of high-height error between each polishing point is established, and the variation rule of the surface arch error of workpiece is simulated by the model. According to the variation rule of the surface arch error, the equal arch error control algorithm is used to achieve arch error consistency and improve processing quality.