Although thermal-aware TSV (Through Silicon Via) cluster's behavior has been studied extensively, the structure of TSV cluster, which is also important to thermal problem in 3D IC (Three Dimensional Integrate Circuit), is ignored. In this paper, a novel structure of TSV cluster is proposed to improve the thermal performance of 3D IC. Models have been established to study the effect of TSV cluster's structure on thermal performance in 3D IC. Simulation results show that the proposed TSV cluster's structure improves the thermal performance of 3D IC, which can help to alleviate the thermal problem.