This paper develops a CAD system (Hcadx) for stiffened waffle cylinder，supported by CADKEY as graphics system. The CAD system can introduce user's operations by menu and can do buckling analysis of stiffened waffle cylinder by empirical formula or by analytic method. It can also obtain optimal parameters by penalty function algorithm and may invoke CADKEY to plot design drawings of stiffened waffle cylinder automatically. It is not necessary to exit Hcadx. These design drawings can be edited easily to become acceptable work drawings.