A rapid cam design and manufacturing simulation system is developed. The system consists of some modules which can be easily extended or updated. In the design module, the profile of disc cam is generated by defining some parameters – rise allowable pressure angle, return allowable pressure angle, the radius of curvature of cam profile etc. And the kinematics analysis of cam is also calculated in this module. Then the profile is transferred into Catia for generating a three dimensional geometry of the cam, and NC program is generated. Last, the NC program is verified by Yulong NC simulation system.