The laser ranging sensor can be applied in the real-time monitoring device for bridge deflection, measuring the bending deformation of the bridge structure. The ranging sensor emits laser and outputs the distance value to the industrial control computer or monitoring system for processing, to determine the deviation and deformation of the bridge. The laser ranging real-time monitoring device has the characteristics of flexibility, speed and high precision. It can provide accurate data, helping engineers monitor the changes of the bridge structure in time, detect potential problems early, and take corresponding maintenance measures to ensure the safety and operation of the bridge.