In order to solve the complexity and low efficiency of the integral calculation method in the curve smoothing of large impeller blades, the curve smoothing method based on shear jerk and local energy was studied. The smoothing requirements of the impeller blades were analyzed. The shear jerk global detection model and local energy smoothing model for the nonsmooth point of blade curve were established. The nonsmooth point detection and smoothing for the discrete points on the shaft curve and cover curve were carried out by using the established models. After smoothing, the maximum shear jerk of the shaft curve and the cover curve are reduced by 41.3% and 39% respectively, which improves the smoothness of the blade curve.