Abstract: In order to inspect the actual dynamic responses of a bridge structure,dynamic loading tests were carried out on the Songtoujiang bridge,a railway continuous beam bridge with a main span of 100 m and a pier of 99 m in high.The natural vibration and dynamic responses of this bridge structure were tested respectively under the conditions that a train passes by and brakes on the bridge at different velocities.In addition,the testing results were compared with the results of vehicle-bridge coupling vibration analyses to show their sameness.The research results show that the bridge has enough vertical stiffness,transverse stiffness and strength,and the safety and comfortability are good though the passing train has an impact to the bridge structure.