Threedimensional (3D) process planning for mechanical machining (〖BF〗KM3DCAPP_M〖BFQ〗 system) was aimed at integrating CAD/CAPP/CAM platform. Based on the analysis of the process file exported by the platform, the integration with UG/CAM on the 〖BF〗KM3DCAPP_M〖BFQ〗 system was integrated. The machining information, which will be mapped to UG/CAM module used of the secondary development functions, was extracted from the technological documents exported by CAPP. The tool path was automatically generated. UG/CAM numerical control (NC) programming was researched mainly, as well as for UG module of the secondary development functions, the transmission and conservation of intermediated data files, the designing and implementation of the tool library and the machining integrating complex features. A case is given to verify the feasibility of system at last.