Abstract: A new method for shape modification of NURBS curves is presented. By using the constrained optimization method, the weights of original curve are changed such that the modified curve passes through a given target point more naturally. A linear equation system with only 3 variables is derived to compute the new weights. Based on the proposed method, an algorithm for contour edition of a 3D face model is also presented considering the specific problem in face modeling. Experimental results demonstrate the effectiveness of the algorithm.