Abstract The high-speed mechanical lapping of a CVD diamond film was carried out by using a resin-bonded diamond wheel. The influences of lapping speed, lapping pressure and lapping time on the surface character, roughness and material removal rate have been studied by using scanning electron microscopy, stylus profilometer, analytical balance and Raman spectroscopy before and after polishing, respectively. The results showed that the material removal mechanism is mainly mechanical wear and the transformation of diamond to non-diamond carbon, and the high-speed mechanical lapping method is a very attractive method for commercializing since it has a high material removal rate.