Abstract: Because of the irregular shape of skin wounds caused by trauma in clinic,the shape of skin flaps is only described by swatch for preoperative design.The method is rough,and the flaps cut often cannot match the wounds and affect the appearance of the wounds.In order to solve such problems,a skin wound morphological flattening algorithm based on hierarchical value is proposed.Firstly,the skin wound is divided into layers,and maps the layered mesh to the plane topologically.After that,simulates the stress and strain of the skin with mechanical method,and optimizes the shape of the skin wound flattened layer by layer.Then,realizes the parallel optimization of the partial wound and the whole wound.Finally,the multi-resolution smoothing technique is used to smooth the developed boundary contour,and fitting the curve to obtain the guidance plan for preoperative flap design.Through the analysis of more than ten cases of skin wounds in different parts,the results show that the results obtained by the algorithm in this paper can better match with the skin wounds,and the average deviation of the area and length after the flattening is reduced to less than 10%.