Abstract: Topology operations are critical in the generation,editing,and optimization of hexahedral meshes.And sheet operations are the most directly efficient and widely used topological modification operations,with sheet insertion operation being the most critical and complex.In order to effectively deal with the complex situations of self-intersecting,self-touching,and multi-sheets generation,an optimization design method of complex sheet insertion operation was proposed to improve the robustness and efficiency.First,the insertion positions were grouped according to the validity conditions.Then,for each group of insertion positions,the local shrink sets,the topological structures of the sheets,and the geometric association of the vertices were designed based on quality prediction,so as to achieve the overall insertion of multiple sheets.Finally,based on the max flow min cut algorithm,the fracture quad set in the remaining groups was complemented to meet the validity conditions.Compared with the traditional sheet insertion method,this method can effectively insert complex sheet and significantly improve the efficiency of multi-sheets insertion.