Many building models are shared in the website. These models generally have high-quality appearances. However, the accuracy of these building models would not be suitable for each case. Therefore, a model refinement approach is proposed in this paper to refine building models by using airborne LiDAR data. The proposed approach consists of three steps, namely, data processing, geometric reconstruction, and model refinement. The first step is to partition a point cloud into several surface models. The second step is to establish geometric relations and constraints of building models, and the last step is to refine building models with the obtained constraints. By using the proposed method, the building models can be refined more efficiently and accurately, and the original geometric relations can be also maintained.