According to the composition of nano ceramics, the paper firstly analyses mechanism of^nano ceramics materials surface machining in ultra precision grinding processes and gives a new critical grinding depth formulation. Then many grinding experiments have been done between the nano ceramics and the common ceramics in the same grinding parameters and grinding methods. Atomic force microscopy (AFM) images show that nano ceramics have outstanding machining performance. Its grinding processes is plastic material cutting like metal cutting, and nicks are clear and brittleness desquamated pits existing in common ceramics grinding surface have not found in nano ceramics grinding surface. Then, according to analyze microcosmic surface quality by AFM, the conclusion is that the nano ceramics surface quality is better than the common ceramics after grinding processes. Concretely, its surface roughness Ra tower above one or two degree than the common ceramics, and there is no crackle, no nick, and no obvious cutting defect. The research results provide experimental and theoretical guides for selection of grinding parameters and grinding methods.