The classification method of bottle cap structure, the secondary development idea and method of SolidWorks API were introduced. The menu loading of bottle cap packaging structure in SolidWorks and the parametric design of caps by means of their typical dimension driven on SolidWorks using Visual Basic and the Access database were researched. The detail function of the system was showed by a case. The purpose was to provide reference for 3D structure design of bottle caps to improve the design efficiency and standardization of bottle cap.