Abstract: Aiming at the modeling process and the processing process of "mask tooth mold" for the complex parts, through analyzing the size of engineering drawings, structure and function of parts, the NX1899 is selected to carry out 3D model modeling design by using the UG 3D software. By comparing different modeling processes and methods, it is found that the "mask tooth mold" model could be established quickly and accurately by creating partial planar structural features and generating complex structural entities through the "whole deformation" command. Based on this model, the program of machining is compiled; then it is concluded that the machining program of complex structure parts with turning law can be worked out efficiently and accurately by using the tool path curve method through comparing different machining programming processes and methods.