Aimed at the demand of NURBS tool path generation for high speed and high precision CNC machining, a new algorithm for generation of NURBS tool path based on linear tool path was proposed. The algorithm found out the segments of linear tool path that adapted to NURBS transformation by using the method of subsection the linear tool path according to the geometry features of linear tool path, and changed them to NURBS. If the interpolation error is bigger than the admit error, then subsection should be done at the data point which has the biggest error and transform them to NURBS over again. The case study indicated that the algorithm is feasibility and practicability. 