Aimed at the feature of radar point cloud of 3D laser on land, combined with the general problem in application of water conservancy such as 3D modeling of hydraulic building, hydraulic safety and slope Monitoring etc, the paper proposed an efficient drawing algorithm of massive point cloud accelerated by GPU. The experiment proved that the algorithm can largely improve the drawing efficiency of massive point cloud ,handle 10GB point cloud and the largest increase value of drawing rate of the algorithm can reach as high as 40% compared with Z-Buffer algorithm.