Abstract: Existing vascular modeling techniques based on subdivision surface cannot deal with vessels of arbitrary topology and cannot provide smooth transition at vessel branch.This paper presents an improved algorithm to overcome such disadvantages.The algorithm first utilizes directed graph to faithfully represent the connections between vascular structures.And then it samples the vessel centerline model to a low resolution by a proposed bidirectional resampling technique.Finally the vessel surface is reconstructed by the Loop subdivision scheme.Experimental results show that the proposed algorithm can robustly handle any complex vascular structures of arbitrary topology and can effectively construct high-quality surfaces for visualization.