Mill-grinding experiments were carried out on SiCp/Al to investigate effects of mill-grinding parameters and grinding wheel parameters on machined surface roughness in this paper. The machined surface topography was also analyzed. Experimental results show that surface roughness increases with increasing feed rate and the depth of the mill-grinding. The effect of mill-grinding speed on surface roughness is low. The machined surface reveals many defects. The fine grit diamond grinding wheel can reduce the surface roughness and decrease the machined surface defect. Compared to the vitrified bonded diamond and electroplated diamond grinding wheels used in the experiment, the resin-based diamond grinding wheel produces a better surface.