Abstract: To realize the fast collision detection between objects, a sphere approximation representation for 3D models is proposed in this paper.It firstly presents a novel 3D model approximation method with inner spheres based on three-dimensional model voxelization.It also reduces the number of inner spheres and enhances the sphere connectivity.Then this approach improves the inner sphere clustering based on the geodesic distance.It obtains meaningful clustering results which can be applied in many applications such as the structure construction of hierarchical inner sphere-trees and the semantic segmentation of 3D models.Experimental results demonstrate the feasibility and effectiveness of this method.