Mathematical descriptions of worm and worm gear and the means of accurate accomplish based on Pro/E are introduced, parametric design is accomplished by the second development, mechanical simulation is carried out,the working case is dynamic observated.

This paper takes the worm and worm gear as an object,discusses a define of character and parameter and the research of worm and worm gear,which could be used in similar hardware,introduces the theory and method of the redevelopment approachor UG with Visual C++.