The environmental vibration test of the bridge can obtain the dynamic (modal) parameters of the bridge structure such as natural vibration frequency, damping ratio and natural vibration mode. These parameters are the base of bridge damage identification, performance evaluation, health inspection and benchmark finite element construction. The measured acceleration signal is subjected to modal analysis to obtain the natural frequency and vibration mode of each step of the bridge structure. The test data is collated and analyzed, and the finite element calculation results are analyzed and compared to understand the actual dynamic characteristics of the structure, which can provide benchmark parameters for bridge maintenance, state assessment and health detection in the future.