Abstract: As the complex shape of blades and the high requirement for welding repair of blades, NURBS(non-uniform rational B-spline) is adopted for trajectory planning. The section curves of blades is composed of leading edge, trailing edge, basin side and vacuum side. In order to get an unified expression and simplify the interpolation process, the order of the expression of leading edge and trailing edge must be increased. Then curve interpolation is carried out based on NURBS. Based on chord error, normal acceleration and programmed feed rate, adaptive control of the feed rate is achieved. This paper proposes a segmented look-ahead algorithm to improve the efficiency. Finally, a simulation is given to verify the feasibility and accuracy of this algorithm.