Abstract: In the course real-time rendering of large scale terrain,if the ground feature model and the terrain model cannot match with each other,cannot feel the verisimilitude of the virtual terrain environment.This paper gives a seamless matching method of the ground feature model based on cross patch and block based error metric ROAM algorithm.Firstly,the conception of spatial raster index is also applied.Then,a new data structure is proposed,and the intersection point set of ground feature’s boundary with terrain triangulation is efficiently sought.Finally,the polygon in the range of the ground feature is calculated based on this intersection point set.Experimental results show that the algorithm proposed can seamlessly match ground feature model with terrain model,and the rendering speed can satisfy the real-time display’s need.