Abstract: Most of the existing simplification algorithms for terrain model might lost some important shape features,such as valley and channel,especially at the low levels of the simplified model,and this will lead to the visual distortion.Based on Garland's greedy insert algorithm,a feature degree of a vertex is introduced.It can change the order of candidates of error metric through calculating the feature degree of vertexes.So the more important vertex of the original model can be preserved.The experimental result shows that the proposed algorithm can maintain more terrain features at the same decimation rate as greedy insert algorithm,while reducing visual distortion effectively.