In 1, CNC programming analysis of the main contents of detail drawings, determine the processing process, mathematical processing, program list, making control medium, program check, input program and workpiece cutting. 2, NC machine tool step (1) analysis of parts drawings and process based on the pattern to the part geometry size, technical requirements for analysis, explicit processing content and requirement, decide, determine the processing sequence processing program, fixture design, tool select, determine reasonable cutter route and the reasonable choice of cutting amount. At the same time also should play the function of a numerical control system and CNC machine tools the ability, correct choice of knife point, entry mode, to minimize such as knife switch, switch and other auxiliary time. (2) mathematical programming, according to the geometric characteristics of the parts, to establish a workpiece coordinate system, according to the drawing requirements, develop the processing route, in the establishment of the workpiece coordinate system, first calculate the movement locus of cutting tool. For the shape of a relatively simple components ( such as composed of straight line and arc parts ), just calculate the geometric elements starting point, end point, a circle center of the arc, Liangji what elements of the intersection point coordinate values. (3) the preparation of parts program list processing route and process parameters are determined, according to the provisions specified in NC system code and block format, the preparation of parts program list. (4) input (5) and the first piece of program verification