Deflection is the key parameter for the evaluation of bridge safety.According to the structural characteristics of bridge

the connected pipe optoelectronic liquid level sensor is adopted for the deflection measurement.The basic principle of the sensor is introduced

the composition of connected pipe optoelectronic liquid level sensor monitoring system is discussed

and the sensor is practically utilized in the deflection monitoring of Dafoshi Yangtze River Bridge.The results show that the data gained from optoelectronic liquid level sensor monitoring system can effectively acquire the bridge deflection

and the system works effectively.