The invention belongs to the technical field of manufacturing technological lugs, and provides a modeling method for a skin part technological lug. For a single-curvature or double-curvature skin part, the extracted skin outer profile is extended in an extrapolation mode according to the curvature to obtain an outer profile flattening face, the model datum face is designed according to the part, four endpoints of a surface patch where the lug is located along one side of the part outer profile are obtained through certain geometry steps, after the four endpoints of a surface patch where the lug is located along one side of the part inner profile are obtained by means of the same principle, the four sets of corresponding endpoints are sequentially connected to obtain the basic appearance outline of the lug, and in a CAD software environment, a lug entity is set up in the form of enveloping solid. Seamless joint between the lug entity and a part geometry body can be ensured, and the accuracy of setting up the lug is ensured.