3D scanning system for dam monitoring based on single-point laser sensor can obtain the spatial 3D information directly, which can realize real-time and efficient monitoring of disasters, such as translation of the dam, crack, break, landslides, etc. So it has a broad application prospect because of high degree of automation, simple operation and field scanning without stop. Research has been focused on the development of 3D laser scanning system based on single-point laser sensor, and the approach of system integration is established. The selection of the core single-point sensor is finished and control system is developed to build the prototype. Based on the statistical analysis of possible values of output parameter, the data ball model and rectangular boundary model are established to investigate the mechanism of system integration. For data distortion resulted from the inconsistence of original points of all sensors, coordinate normalization algorithm is proposed to complete the system calibration. Besides, the correctness and necessity of the system calibration work is verified through real experiment.