The formulation of machining process regulations is an important program document that must be implemented for large machining plants. In the process of customizing machining process regulations in large machining plants, in addition to formulating the selection principle of positioning benchmarks, attention should also be paid to the selection of machining methods. , The structure and shape of precision mechanical parts are composed of basic geometric surfaces. The same surface can choose a variety of different processing methods, but different processing methods will greatly affect the processing quality, processing efficiency and processing costs. Therefore, in the machining process specification, relevant processing method selection principles should be formulated, so that the efficiency and quality of precision mechanical parts processing can be better improved, and the processing cost can be better reduced.