The application of hard and brittle materials become wider and wider because its self-characteristics. It is used widely in finish machining of products, such as memory record device, information products, precision instrument, etc. Traditional grinding-polishing methods have not suited for precision machining requirements of hard and brittle materials. Carbide and ceramic are chosen as workpiece. Diamond polishing film is chosen as polishing tool. Polishing experiments are done by using self-made film polishing machine with high speed and cooling inside. Polishing mechanism and polishing technology of what polishing film polishes hard and brittle materials will be studied by changing polishing speed and diamond grain size and so on. The experimental study of wear shape of gringding grain, desquamation process of grain and surface quality of workpiece will be done in this paper so that the reasonable technology of polishing hard and brittle materials with high productivity is obtained. It enrich and perfect the ultra-precision machining theory. A new method of ultra-precision lapping and polishing of hard and brittle materials is provided.