An　approach　of　regions　segmentation　algorithm　in　triangle　meshes　based　on　threshold　angle　of　the　normal　vectors　is　proposed.　In　this　paper,　a　set　of　threshold　angles　is　used　to　identify　features　and　segment　different　surfaces,　and　then　the　non-feature　regions　based　on　least　squares　method　are　fitted　and　the　corresponding　fitting　precision　are　obtained.　Finally,　the　best　threshold　angle　of　each　region　is　determined　according　to　the　comparison　the　above　fitting　precisions　and　each　non-feature　region　points　are　obtained　exactly.　This　method　can　improve　the　precision　of　feature　extraction　and　region　segmentation　in　some　hybrid　blend　region.　Examples　are　given　to　prove　the　effectiveness　and　the　processing　flexibility　and　stability　of　the　proposed　approach.　©　(2010)　Trans　Tech　Publications.