Abstract: UG’s CAM （Computer Aided Manufacturing） module is an important part of the UG software, mainly used to generate CNC machining programs for mechanical parts, can achieve the processing of complex parts and special parts programming. In this paper, the use of TCL scripting language in the UG post-processing constructor customized FANUC system post-processing program, to achieve the output of the program name, and in the program header output machining time, machining allowances, tool information, and other technical issues. Finally, by running the program through simulation and using machine tools to machine parts, thus verifying the stability and reliability of the post-processor to meet the needs of three-axis parts milling, drilling, reaming.