Under the wind load, a structure produces the vortex vibration effect, which threatens the safety and durability of a bridge. Because of its low wind speed and high frequency, it poses a serious safety hazard to safety in the construction state and the traffic safety in the completed state. Therefore, in this paper, a numerical simulation method of vortex-introduced vibration (VIV) performance in the main girder of cable-stayed bridge based on bidirectional fluid-solid coupling is proposed. Taking CFD control equation as the constraint condition, the main girder model is divided into the calculation domain, grid division and boundary condition setting using the Gambit pre-processing software, and a vortex-induced force (VIF) model of the main girder based on the simulation process is proposed. Finally, based on the parameters of the main girder section model, the numerical simulation results of the vortex vibration performance of the main girder are analysed, and the results show that the vortex vibration test results are basically consistent.