The 304 stainless steel substrate was grinded to 1200# (1# process), 2000# (2# process) by sandpaper in sequence and grinded to 2000# and polished by diamond polishing paste with size of 0.5 μm (3# process), respectively, and then the CrMoN coating was deposited on the surface. The phase composition, surface and cross-section morphology, hardness, surface hydrophobicity, corrosion resistance and conductivity of the coating were studied. The results show that the roughness of the coating surface deposited on the substrate surface pretreated with 1# process was the largest, followed by that pretreated with 2# process, and the roughness that pretreated with 3# process was smallest. The phase of the coating consisted of CrN, Cr2N and Mo2N. With decreasing substrate surface roughness, the microhardness, free corrosion potential and water contact angle of the coating increased, and the corrosion current density and interface contact resistance after polarization decreased. The comprehensive properties of the CrMoN coating deposited on the substrate surface pretreated with 2# process were excellent, which were close to those pretreated with 3# process.