Abstract: Classical approach of implementing graphic library for CAD systems is classified into two categories. The first is to build all kinds of unchangeable graphic components by end user and put them into a library. The second is to break down the components into graphic primitives and each primitives is described by a programming function, that is to say, the graphic library is equivalent to a programming library. In contrast to these two approaches of implementing graphic library, this paper offers a paradigm which supports parametric design, provides LOD (level of detail) description of components, satisfies the whole life-cycle requirements of graphical presentation of components, and facilitates the project management of engineering design. This approach has been realized in a plant design system PDSOFT.