In order to reveal the mechanism of vibration generation and transmission of high -speed railway bridge structure, the vibration characteristics of elevated box girder structure induced by 300 km/h high-speed train were studied by numerical method and field measurement respectively. Firstly, a three-dimensional finite element dynamic model of the simply supported elevated box girder is established to analyze the vibration char acteristics and transmission law of the elevated box girder structure when the train passes at a speed of 300 km/h. Then, an elevated track in Gaoan-Nanchang section of Shanghai-Kunming high-speed railway was selected to conduct field tests on the vibration of the bridge structure caused by high-speed trains, and the finite element calculation results were compared with the measured results. The results show that the finite element analysis is in good agreement with the field measurement results in the range of 20 Hz to 400 Hz. The dominant frequency of bridge structure vibration is 31.5~125 Hz, the peak frequency is 31.5~63 Hz, and there is an obvious trough at 16 Hz. When the frequency is greater than 200 Hz, the vibration level of the acceleration of the bridge struc-ture drops sharply. Therefore, the vibration reduction design of the bridge structure can be carried out accordingto the frequency of 31.5~63 Hz. The vibration level of the maximum acceleration of the bridge roof is 88.59~ 100.48 dB, and the corresponding peak frequency is 31.5 Hz and 40 Hz. The maximum acceleration vibration level of the bridge floor is 82.96~94.29 dB, and the corresponding peak frequency is 31.5 Hz and 63 Hz. The vibration of the box girder floor contributes the most to the vibration of the bridge structure.