Aiming at the need of high-precision detection of aeroengine blade profile, the 3D reconstruction technology of blade profile based on laser scanning point cloud was described, and the error of profile reconstruction was analyzed. The measurement data was processed through the mathematical model of point → line → surface. First, the smoothing curve is fitted by the first-order end-point vector method of point cloud, then the Non-Uniform Rational B-Splines surface is fitted based on the section curve, smooth surface method is used to reconstruct the surface, and the reconstruction error is analysised by calculating the minimum distance between the space measuring point and the surface. Finally, the algorithm is verified by the blade profile laser measuring device. The experimental results show that the reconstruction error is less than 0.015 mm, which meets the evaluation requirements of blade profile quality.