Abstract: A layer construction of scene database for virtual BUAA(Beijing University of Aeronautics and Astronautics) campus has been put forward, a paging algorithm based on model control planes has been provided, three scene complexity simplification strategies of redundant modeling data simplification, texture mapping and multiple LOD(Level of Detail) models have been realized. Much attention has been paid to discussing the picking approaches of virtual entity based on the standard two dimension input device and manipulation of restricted moving entity has been realized. And finally a brief introduction has been made to the realization of general walkthrough engine frame work which has nothing to do with models.