Abstract: With the acceleration of China's economy, the construction of urban transportation facilities is constantly increasing. As an important part of urban transportation, bridges are also constantly updating and improving the technology in the aspects of construction and testing. After long-term operation due to the uneven load and natural uncontrollable external force, bridge has local deformation, cracks and other diseases. Because the bridge across the water, the influence of traffic and natural factors, conventional GNSS receiver, all station such as measuring instrument is difficult to quickly and accurate obtain bridge full space information data, and 3D laser scanning due to its high operation efficiency, non-contact has the advantages of traditional measuring equipment.Taking Runyang bridge in Jiangsu province as an example, this paper discusses the application of 3D laser scanning technology in bridge deformation monitoring, and introduces the steps of field scanning, point cloud splicing denoising, achievement map drawing, and deformation analysis in detail, which provide reference experience for the application of new means of bridge monitoring.

Key words: 3D laser scanning, point cloud, bridge, deformation monitoring