Excessive errors in the machining process affect the performance of mechanical products. In the study of analytical machinery.On the basis of the source of technical error in the processing technology, the source of error is determined, mainly including positioning error,machine tool manufacturing errors and tool geometric errors; The corresponding error control methods, including error compensation, are analyzed method, direct error reduction method and error grouping method, and compare; Finally, three error control parties are proposed.Characteristics of the application of the method in different machining. It has reference value for practical work.