Because of the cartoning machine has different box size,feeding cam size,stroke and other parameters are changed,the feeding cam need to be replaced frequently.The traditional CAD/CAM software is both time-consuming and difficult to design the cam.On the basis of secondary development tools of UG,the software system of cam parameter is developed combined with VC++6.0.Through running show that the system has a good human-computer interaction,users only need to input the key parameters to modify can get the new three-dimensional model,the design time is reduced and a cam parametric design is achieved.And a reference for cam CNC machining,simulation design and manufacturing and parametric design is provided.