Abstract: An approach for 3D environment modeling is proposed to establish the topology-elevation model of outdoor scenes. After projecting laser points into 2D grids, the clustering algorithm classifies the points into vertical units and horizontal units for purpose of describing overhanging structures. The discrete samples of vertical units layered by height are connected to form topological structures, which are utilized to identify typical objects by means of BOW (Bag of words) classifier. A hierarchical strategy, in which topological structures and elevation units are used for scene matching separately, is presented for achieving a globally consistent registration. The constraints extracted from environment features and elevation map are used to guide mobile robot's autonomous path planning in outdoor environment. Experiment results and data analysis show the validity and practicability of the proposed approaches in 3D environment modeling and path planning.