Post processing is an important step in the technology of automatic NC programming and CAM. Constructing the post processing module for fiveaxis CNC machine was studied based on UG/Post Builder85, the method and basic procedure of the construction of the post processing module were described, and the post processing module for the two turntable five axis machining center was constructed. Taking the 3D model of goddess Venus as example, the post processing module was applied to carry out post processing and machining program was produced automatically.The practice proves that the machining result of goddess Venus part accords with the requirements of practical machining. This method of constructing the post processing module for fiveaxis CNC machine can be applied to other fiveaxis CNC machine tool. It has very strong and practical value.