As a relatively complex part of aero-engine turbine blades, the integral impeller is characterized by complex space, high steepness, and distortion. An actual five-axis computerized numerical control (CNC) machining process unaffected by the machining quality and accuracy of a large curvature range. Consequently, knowing how to reasonably adjust the feed speed of a path in view of further improving the efficiency has always been difficult. This research adopts the method of combining computer-aided manufacturing (CAM) and CNC and proposes a direct interpolation algorithm for the double non-uniform rational B-spline curves based on the typical characteristics of the integral impeller. First, in the CNC, the integral impeller is divided into high-speed regions and three-dimensional characteristic parameters of the integral impeller in CAM. Second, in the low-speed area, the feature-divided high- and low-speed areas are discretized on the basis of the interpolation period and equal arc length. Then, the low-speed area speed is adjusted to meet the kinematic constraints according to the dichotomous configuration. Finally, the discrete speed is smoothly filtered by the Finite Impulse Response (FIR) filter to be able to meet the dynamic response characteristics of the machine tool. Simulations and experiments show that the algorithm can effectively improve the speed and smoothness of the inlet and exhaust edges of the overall impeller, effectively reduce the calculation amount of the numerical control system, and improve the overall machining efficiency of the impeller under the requirements of machining accuracy.