The surface of porous valve plates for automobile airconditioning compressor is mostly polished by hard grinding process. There are problems such as large surface roughness, burrs at the hole edge, and poor sealing between valve blocks and valve plates. To solve the above problems, silicon carbide fiber tow polishing was proposed to instead of traditional grinding. The theoretical analysis of the motion trajectory of silicon carbide fiber tow polishing was completed. MATLAB software was used to optimize the motion parameters, and the influence of brush head and work piece different speeds on the motion trajectory was compared and analyzed. Intelligent doublesided polishing machine was designed and manufactured, and the motion parameters and polishing effect were verified by experiments. The research results show that using this method, the polishing track of valve plate surface is changed into a small uniform curved crossgrid, burrs at the hole edges is eliminated and chamfer is made at the hole edges,so the surface roughness of the valve plate is improved.