Aimed at the modeling difficulty that contour graph of globoidal indexing cam is not expanding, the paper brought forward a new reform method of modeling. The digital model was founded by establishing eligible points, joining points to lines, joining lines to surfaces and molding surfaces to the entity. By building variable numerical group, the CAD could exchange data dynamically in real time with database, while the designing work was carried out. It can realize the share and reuse and online loading of data. The results showed that the method can modify data dynamically and improve the precision, and can provide important data for parts' machining and numerical control programming, sequentially redounding to the further study and manufacture of globoidal indexing cam.