Abstract: In order to solve the problems of frequent acceleration and deceleration, slow processing speed and low processing quality in the traditional CNC system in the continuous and micro-line segment tool path processing with discrete curves and surfaces, an adaptive NURBS curve fitting algorithm for tool path based on precision control is proposed. The algorithm extracts the main feature points of the tool path of continuous micro-line segments, and performs the iteration fitting of adaptive feature points based on precision control. The simulation results show that the algorithm can effectively improve the calculation efficiency and compress the data volume under the condition of ensuring the fitting precision.