Abstract: A smooth terrain rendering algorithm based on GPU is proposed to solve time and space discontinuity problems during terrain visualization. The algorithm is a coarse-grained aggregated LOD method. Based on the smooth geomorph idea, the terrain chunk is divided into regions and the morphing weight of every vertex in the region is evaluated in real time for current morphing operation. The morphing weight involves the transition between different detail levels and the level difference between neighboring chunks. Through this morphing operation, during the terrain rendering, the smooth transition between different LOD levels and different terrain chunks can be achieved at the same time, and a smooth terrain walkthrough can be gotten. The method is implemented in a GPU-oriented way and the main computation for morphing is accomplished on GPU. The tests show that the algorithm can generate the smooth terrain scene at a high frame rate, and the cracks and pops during rendering can be eliminated efficiently.