In current research, there is an urgent need to quickly reconstruct 3D scenes from detected scene data for scenario design, rapid verification, and other applications across various fields. This paper proposes a method for rapid 3D scene reconstruction based on the U-Net network model. By dividing real-world scenes with complex and multi-scale elements into terrain elements, ground elements, and surface elements based on their size, and using image recognition and segmentation techniques to extract these multi-scale elements, the method leverages the UE4 engine to match and reconstruct the data. This approach enables the rapid establishment of 3D scenes.