Abstract: This paper presented an algorithm for military symbols rendering,focusing on overlaying irregular military symbols on 3D multi-resolution terrain.The algorithm was based on displacement mapping.First,terrain was smoothed using the programmable fragment processor on GPU to wipe off local details and reserve the main hypsography.The smoothed result was rendered to a displacement texture on the fly.Then,2D outlines of irregular military symbols were generated to trim NURBS surfaces to create military symbol grids.Finally,according to the displacement texture,all vertices of the military symbol grids were displaced using the programmable vertex processor on GPU.The algorithm allows high-quality overlay of military symbols on virtual landscapes and can meet the real-time requirement of interactive edit and dynamic plotting.