Abstract: In order to investigate the aerodynamic characteristics of the triple-box girder and the aerodynamic interference between trains and the triple-box girder of a bridge, wind tunnel tests were carried out to discuss the effects of the web shape and appurtenant facilities as well as the Reynolds number on the aerodynamic force coefficients of the triple-box girder. The results indicate that the variation trend of drag coefficient of the triple-box girder with the wind attack angle is very similar to that of the twin-box girder, i.e., it first decreases and then increases with a turning point in the wind attack angle range of −2°～0°. The web type only has a minor effect on the aerodynamic force coefficients, while appurtenant facilities such as the wind barrier has significant effects. Within the Reynolds number range of the tests, bare girders with two different webs (namely curved type and linear type) both have obvious Reynolds number effects, but a clear difference exists between them: for the girder with a linear-type web, only the drag coefficient is sensitive to the Reynolds number change; while for the girder with a curved-type web, both drag and moment coefficients are sensitive to the Reynolds number variation. The aerodynamic interference effect between the train and the girder is remarkable, and such an effect varies with the wind attack angle. When a single train exists, the relative horizontal position between the train and the girder has little effect on aerodynamic force coefficients of the girder. When two trains meet each other, the drag coefficient of the girder is significantly reduced compared to that without trains or with a single train, and the aerodynamic force of the leeward train first drops and then increases suddenly, which is unfavorable for the traffic safety.