Abstract: A coupled vibration analysis model is established for train-bridge system subjected to floating-ice collision load. The collision load time history curve of floating-ice obtained via site experiment is applied on the bridge piers in transient style. The dynamic responses of railway bridges subjected to floating-ice collision and their influences on the running safety of high-speed trains are analyzed by computer simulation. Using the computer code programmed by the authors to simulate the whole histories of a train traveling on a seven-span simply-supported bridge with 24m box girders when the floating-ice strikes on bridge piers, the dynamic responses of the bridge and the train vehicles are studied. The calculation results show that the lateral acceleration of the bridge and running safety indices such as the derailment factors and offload factors of train vehicles exceed the corresponding allowances when the train speed is higher than 250 km/h, indicating that collision of floating-ice has obvious effect on the coupled vibration responses of train-bridge system.