An active smoothing technology for the surface MSF error of high steepness aspheric elements was proposed. By constructing the off-axis machining contact model of aspheric element, the distribution of misalignment in the machining process was obtained, and the active deformation grinding disc was designed. The finite element analysis method was used to simulate the relationship between the material, thickness and structure of the grinding plate in the process of active smoothing, and the optimal active smoothing parameters were obtained. The experimental results verify that the accuracy of the calculation model and the active smoothing technology play a better smoothing effect on the MSF error of high steepness aspheric components.