Through analyzing the characteristics of commonly used interpolation algorithms in the computer numerical control (CNC) system, a novel real-time NURBS interpolation algorithm is proposed. The algorithm includes velocity planning and real-time interpolation. The velocity planning module considers the maximum contour errors during the machining of workpieces to ensure the continuous acceleration of the process of high-speed operation, which enables the CNC machine tools to run smoothly and avoids intense vibration in high speed CNC machining. The real-time interpolation module uses the secant iteration method to calculate the interpolation parameters, which can dominate the feedrate fluctuation to ideal level and further reduce the tremor of the CNC machine tools. Simulation experimental results show that the NURBS interpolation algorithm proposed in the paper can reduce machine vibration and implement high-quality CNC processing.