In order to study the structural noise of simply supported box girder, a 32 m simply supported box girder was taken as the research object to carry out a vehicle-bridge coupling dynamic analysis to figure out the vertical wheel-rail force under the effect of track irregularity. In the sound field analysis model of the simply supported box girder with the vertical wheel-rail force as the excitation, frequency distribution characteristics and propagation laws of the sound pressure were analyzed by the method of combining boundary element and finite element with the dynamic response result of the simply supported box girder as the boundary condition.The influence of traveling speed and plate thickness on the structural noise of simply supported box girder was mainly studied. Studies show that the frequency band of bridge structure noise is mainly below 100 Hz, and the noise sound pressure level above the roof is the largest; structure noise has obvious attenuation characteristics during the propagation process, and the noise sound pressure level decreases with the increase of the propagation distance; the higher the vehicle operating speed is, the greater the structural noise sound pressure is; the greater the box girder stiffness and roof thickness are, the lower the noise sound pressure level is;under the same load, the structural noise sound pressure level radiated by the single-box double-chamber box girder is lower than that of the single-box single-chamber box girder.