At present, the laser 3D image reconstruction method has some defects, such as low efficiency and long time. In order to obtain a better effect of laser 3D image reconstruction, a new high-precision and fast reconstruction method of laser 3D image is proposed. This method uses nonlinear improved method to calculate the position and spatial coordinate points of 3D camera, and makes its error distribution uniform. At the same time, the sparse matrix method is used to automatically detect the laser point cloud, remove noise and obstacles, and optimize the point cloud data, so as to get a more accurate laser three-dimensional image. The first-order partial derivative of laser three-dimensional image is calculated by differential approximation strategy, and the approximate edge position in the image is preliminarily determined. The edge features of three-dimensional images are extracted by ant colony algorithm, and the reconstruction coordinate points of edge features of three-dimensional laser images are calculated. Finally, the reconstruction of three-dimensional laser images is realized. The experimental results show that this method can extract the edge contour of laser 3D image with high accuracy, and the reconstruction accuracy is ninety-seven percent, and the reconstruction time is 35 ms.