The work aims to improve surface quality of sapphire after being ground. The process method of ultrasonic polishing was combined with magnetic abrasive finishing, surface roughness values Rp, Rv, Rz and Ra were taken as evaluation indexes. Ultrasonic polishing is a kind of non-contact precision grinding method, and magnetic abrasive finishing also belongs to flexible manufacturing mode, which are combined in order to improve machining efficiency and surface quality. For ultrasonic polishing, constant current ultrasonic power and equivalent impedance control feed mode were applied, and corresponding processing surface was obtained by changing different impedance threshold. For magnetic abrasive finishing, rotating magnetic abrasive finishing with permanent magnets was applied, and effects on machining surface were observed by adjusting rotational speed and replacing grinding particle size. Technological test was designed with revolving magnetic speed, impedance threshold, and magnetic abrasive size as three main technical parameters including. Based upon ultrasonic polishing and magnetic abrasive finishing, surface roughness(Rp, Rv, Rz, Ra) of sapphire finished surface was 1.992, 1.313, 3.305, 0.055 μｍ, respectively provided that rotating magnetic field rotation speed was 1200 r/min, magnetic abrasive mesh was 120 and impedance threshold was 330 Ω. Magnetic abrasive size has obvious effects on the surface roughness value when using ultrasonic polishing and magnetic abrasive finishing for sapphire and speed of rotating magnetic field and impedance threshold value are constant; the speed of rotating magnetic field and impedance threshold mainly have greater influence on surface roughness of Rp and Rv if magnetic abrasive size is consistent.