The aim of this paper is to compare and analyze the polishing results of sapphire wafers with different crystal orientations, optimize processing parameters, and explore the influence of crystal orientation on the polishing results. Sapphire wafers (50.8 mm) with A-plane and C-plane were selected as the research objects, and the controlled variable method was adopted. The processing load (9.87, 14.81, 19.75 kPa) and the polishing plate rotation speed (20, 40, 60, 80 r/min) were used as variables, respectively. Surface roughness Ra and material removal rate MRR were chosen as the evaluation indicators. The surface morphology of the sapphire wafers before and after polishing were tested The polishing experiments of sapphire wafers with two crystal orientations were carried out. The surface morphology of Sapphire Wafers before and after polishing was compared with the help of 3D surface profiler and scanning electron microscope SEM. The processing parameters were optimized according to the experiment results. The surface roughness and material removal rate of A-plane and C-plane sapphire wafers showed a rapid decline at first, gradually slowed down and finally tended to be stable. When the parameter combination of rotating speed 60 r/min and load 14.81 kPa is selected, the minimum roughness and maximum material removal rate of the two wafers are obtained, and the A-plane Ra= 24.874 nm and MRR = 3.715 nm/min are finally obtained; C-plane Ra=2.763 nm, MRR=7.647 nm/min, and the material removal rate of C-plane is 2.1~2.5 times that of A-plane. The crystal orientation of sapphire has a significant impact on the result of polishing. Moreover, under the same polishing conditions, compared to A-plane sapphire wafer, C-plane is easier to obtain nano-level surface quality and higher material removal rate. that is to say, C-plane sapphire wafers are easier to process.