In order to analyze the influence of process parameters on the surface polishing results of ultrafast laser polishing hard and brittle optical materials during the polishing process， based on the interaction mechanism of ultrafast laser and hard and brittle dielectric materials， according to the analytical model of the removal function of ultrafast laser polishing dielectric materials， a single-pulse material removal model related to the two processing parameters of defocus and incident angle is established. Using the software and according to the change law of the multi-pulse ablation threshold of dielectric materials， a computational model of ultrafast-laser polishing of hard and brittle optical materials is established， and the results of ultrafast-laser polishing of the material surface under different incident angles and advance lengths are calculated by using the model. This calculation model can directly explain the results of ultrafast laser polishing optical materials， and provide new theoretical guidance for the selection of appropriate laser polishing process parameters and methods.