Abstract: Focusing on detail preserving in triangle mesh model simplification,matching of the local average size of meshes surrounding a vertex or a triangle is taken as the criterion of region growth,and the matching threshold is lowering down in proportion to the increment of mesh density in a region.At first, the area of each mesh and the ir average value surrounding each vertex are computed and the process of region growth is started repetitively from a seed of the largest mesh.After completion of preliminary segmentation, merging of compatible separate regions and smoothing of the ir boundaries are undertaken. Experiment shows that this approach is fast and effective,meeting the requirement of keeping local features in mesh simplification.