3D evaluation method of cutting surface topography for C/Ph composites was established. The cutting surface was measured by Talyscan 150, using 3D non-contact measurement. Through the results of 2D and 3D roughness evaluating for C/Ph composite and Duralumin, the 2D evaluation method of the cutting surface topography of C/Ph composite loses a lot of information, the characteristics of the surface topography of C/Ph composite can be comprehensively and authentically evaluated only by 3D evaluation method. Furthermore, 3D amplitude and spatial parameters were adopted to evaluate the surface. The results show that: the topography of the C/Ph composite is anisotropic, there are more valleys in the machined surface of C/Ph than that of duralumin, and there are not obvious feeding textures for C/Ph, which indicates the machining mechanism is different from the metal. In conclusion, the topography of the C/Ph composite cutting surface is anisotropic; the cutting surface of C/Ph composite needs 3D evaluation method.