Abstract: A fast auto-partition algorithm according to designing meaning for a triangular mesh model,which has four steps,is proposed.First,the spacial index structure of the triangular mesh model is established based on the R*-tree.Second,the intersectant triangles are obtained with depth-first traversing based on the special index structure.Third,the intersectant triangles are subdivided to get after-partition model without sawtooth,which is proved to be able to partite all types of triangular mesh models efficiently,and can avoid sawtooth in partition areas.