Abstract: A method to reconstruct 3D building rooftops by the integration of LiDAR data and orthophoto is proposed.It consists of three main steps:rooftop patch extraction,rooftop line determination and 3D rooftop model reconstruction.Two new algorithms are proposed:a method on rooftop patch detection by integrating triangle clusters and dynamic triangle propagation;an algorithm based on LiDAR data and imagery for precise rooftop line extraction.The results demonstrate that complex building rooftops can be reconstructed well by proposed method.For the reconstructed 3D rooftop models in test area 1 and 2,the correctness are 86%,90%,respectively;the completeness are 85%,88%,respectively;the geoposition accuracy are 0.39 m,0.31 m,respectively.