Abstract: In order to improve the accuracy and efficiency of the reduction and reconstruction of point cloud data in reverse engineering, the application of B spline surface fitting in curvature reduction and surface reconstruction was improved. The 3D scanning technology, 3D design, point cloud data simplification and model reconstruction in reverse engineering were applied and studied in depth and detail. A reduction algorithm based on B-spline surface transition/fine tuning was proposed. The research was applied to reverse manufacturing of impeller. Point cloud data can be reconstructed by 3D scanning, and the point cloud data can be encapsulated and simplified reasonably. Surface reconstruction and 3D redesign were carried out, and the smoothness and precision of the product were analyzed at the same time. Finally, the product model sample was printed out by the rapid prototyping machine. The research results show that the proposed method not only improves the efficiency of surface modeling, but also improves the accuracy of inverse modeling.