In order to study the influence of position change of maintenance track on aerodynamic stability of structures, a long-span suspension bridge with closed steel box girder section is taken as the research object. The vortex vibration displacement response of the structure under different positions of maintenance tracks is obtained through the segmental model wind tunnel test. The computational fluid dynamics (CFD) method is used to simulate the flow field around the section under typical working conditions, and the internal mechanism of the influence of the maintenance track position on the vortex vibration characteristics of the section is further explored. The research results show that the location of the maintenance track has obvious influence on the vertical and torsional vortex vibration of the section. When the maintenance track is located at the middle or edge, the vortex vibration stability of the section will be deteriorated. Especially when the maintenance track is located at the edge, large amplitude torsional vibration will be induced. The numerical simulation results of the flow field show that the vortex vibration is mainly caused by the wake vortex shedding, and the change of the position of the maintenance track will change the size and position of the wake vortex shedding, thus further affecting the vortex vibration stability of the section. When the relative position of the track is 0.75, the vortex near the wake and repair track is weak and the flow field stability is optimal.