Aiming at the requirement of automatic real-time detection for safe operation of bridge structure,an embedded image type bridge deflection detection scheme using laser datum is proposed,a visual measurement data reading method and hardware system based on transmission target are designed.On the basis of analyzing,the cause of bridge span down deflection,the principle and constitutes of the laser datum bridge deflection detection system,the hardware block diagram of system are presented,the structure diagrams of transmissivity intelligent target which can automatic convert light spot is designed,and the principle of human-interactive and remote transmission module,computer monitoring system and analysis software are also presented.The method solves the contradiction between high precision and real-time in measuring the bridge deflection,ensure the precision and efficiency of the measurement system.It is found by the laboratory platform that the measurement error of this method is less than 300 μm,and the data update rate is less than 40 ms,which meets the requirements of high precision and real-time.