In this paper,curve fitting of 3-D points generated by G01 codes and interpolation based on quadratic B-splines are studied.Feature points of G01 codes are selected using an adaptive method.Next,quadratic B-splines are obtained as the fitting curve by interpolating these feature points.Computations required in implementing the velocity planning algorithm mentioned by Timer et al.are very complicated because of the appearance of high-order curves.An improved time-optimal method for the quadratic B-spline curves is presented to circumvent this issue.The algorithms are verified with simulations as well as on real CNC machines. In this paper, curve fitting of 3-D points generated by G01 codes and interpolation based on quadratic B-splines are studied .Feature points of G01 codes are selected using an adaptive method .Next, quadratic B-splines are obtained as fitting curve by interpolating these feature points. Computations required in implementing the velocity planning algorithm mentioned by Timer et al. very very complicated because of the appearance of high-order curves. An improved time-optimal method for the quadratic B-spline curves is presented to circumvent this issue. The algorithms are verified with simulations as well as on real CNC machines.