Abstract: This paper presents a 3D laser point cloud-based description method of travel environment for mobile robot. Based on laser data coordinate transformation from sphere to cylinder, environment perception cylinder is configured. In the cylinder, terrain traversability in travel environment is analyzed with radial slope and tangential slope of point cloud, according to 3D lidar scanning sequence. Furthermore, candidate road point cloud can be obtained from the result of terrain description. Experimental results indicate that the method can make mobile robot recognize its travel environment correctly.