Abstract: An algorithm inquiring topological neighbors for 3d scattered point-cloud based on the Voronoi Diagram of local point-set is proposed,which has four steps: first,R*-tree was applied and improved to organize the spatial indexing structure of scattered point-cloud;second,the neighboring points set of the sampling point was gain according to the algorithm searching for k-nearest neighbors;third,the topological neighbors reference data of the sampling point were obtained through eccentric and adaptive expansion;fourth,the Voronoi topological neighbors inquiring was realized according to Voronoi diagram of topological neighbors reference data.It was proved that this algorithm can obtain topological neighbors of arbitrary complicated scattered point-cloud accurately and efficiently through analyzing time complexity and doing related experiments.