In the lapping of sintered SiC with diamond slurry, many scratches are generated to the directions at random. The surface texture of SiC depends on its mechanical functions. When the motion of workpieces is controlled in the mutual lapping, the unidirectional texture generated on the lapped surface having the special characteristics. Most evaluations of machined surface are carried out based on some surface roughness parameters except Angular Spectrum in ISO25178. The new evaluation of finished surface of SiC by lapping is proposed based on the surface topography in this study. As a result, the proposed evaluation method of surface has correlation with a surface function rather than practical geometric evaluation parameters.