Abstract: The highlight line model is a powerful tool in assessing the fairness of a surface.A new method is presented to remove the local unfairness of NURBS surface by adjusting its normal vectors. The nonlinear equations of highlight-line model is transformed into linear equations,and hence greatly reduce the complexity of computation. Modification of the control points of the surface is achieved by solving a system of linear equations.The new NURBS surface have the certain normal that designer specifies.The method is intuitive and suitable for rea-l time interactive design,it allows a designer to improve the fairness of NURBS surface by simple operations.Examples of testing the effectiveness of the new method are included.