Alter analyzing existing methods of constructing hierarchical model.this paper present a new simplification method for polyhedral model based on feature angle criterion.It is one of the important techniques for constructing hierarchical model.It consists of three parts:1. preprocessing data including creating topological structure and some basic computation;2. deciding whether a vertex should be deleted according to feature angle criterion;3. filling hole using a modified local greedy triangulation algorithm and updating topological structure of model.At the end of the paper.is given a sample of hierarchical model through defining different feature angle threshold.