Focusing on the problem of NURBS curve interpolation in high speed manufacture, a new trajectory planning algorithm, which is suitable for chord error closed loop controlled interpolator is proposed. This tragjectory can determine accelerating, decelerating or maintenance last velocity in the next period via judging the braking distance. By the way of testing different calculating time under different CPU core, the real-time characteristic is validated. The simulation shows that chord error closed loop interpolator can automatically adjust the velocity to satisfying the precision demand, through calculating the curvature. In addition, it can assure that the maximal velocity and the acceleration were equal to the referenced parameters and machine runs with the dynamic characteristic of operator set completely.