In order to design and manufacture spatial cams rapidly and precisely, a CAD/CAM system is introduced for the design of 3D modeling and automatic programming in NC machining. Based on Pro/ENGINEER software used widely in CAD/CAM systems, according to the curve equation of spatial cam followers motion specification, the follower displacement curve is drawn quickly and accurately, then the 3D modeling of spatial cam is created using Pro/Feature module in accordance with this curve, afterwards, the quality of contour surface of spatial cam is inspected by the use of surface analysis, the result of which is fed back to the modeling design of spatial cam; after analyzing the machined theory of spatial cam, the NC machining code for it is programmed automatically according to this theory and the modeling completed in the Pro/Manufacture module. To design and manufacture spatial cams by this process can be modified circularly on the basis of the surface checking information in terms of feedback data, so the contour surfaces created have high precision, excellent kinematic characteristics and dynamic characteristics.