Pontoon bridge equipment is an important equipment to overcome the obstacles of large and medium-sized rivers. Aiming at the problems of large number of pontoon bridge units, complex operation process, unclear operation situation and low efficiency of manual command in the process of pontoon bridge equipment erection, a high-precision monitoring system for pontoon bridge motion state is designed. This system is based on Beidou technology, RTK (Real-Time Kinematic) technology, and wireless ad hoc network technology to achieve centimeter-level positioning accuracy, high-precision all-weather real-time monitoring, and situational display of the pontoon bridge"s motion state data, ensuring strong reliability. A certain type of pontoon bridge equipment is tested in a certain section of the Yangtze River, and compared with the traditional erection mode, the time of the pontoon bridge erection assisted by the system is shortened by 49.15%, which shows that the system can effectively improve the efficiency of pontoon bridge erection command and dispatch.