To understand the influence of the railing heights on the vortex-induced vibration （VIV） performance of the girder， and to reveal its mechanism， a segment model wind tunnel test including dynamic pressure and vibration measurement was carried out. The VIV response， aerodynamic forces， mean and fluctuating wind pressure coefficients， frequency domain characteristics， and the distribution of contribution coefficient of local lift on VIV were comprehensively analyzed. The results indicate that after installing the railings， the mean wind pressure coefficient is increased， and the fluctuating wind pressure change is complicated. The predominant frequency of fluctuating wind pressure is almost consistent with the natural frequency of the model. And the contribution function of the local lift on VIV increases. Therefore， the VIV phenomenon is far more marked. And the influence of variation in railing height on the surface wind pressure coefficient of the girder is negligible， but it has a great influence on the distribution of fluctuating wind pressure coefficient and the amplitude of fluctuating pressure power spectrum； with different railing heights， local lift in the front and tail areas of the upper surface of the main beam contribute differently to the vortex. When the contribution increases， the VIV response of the main beam increases； when the railing height is 45% of times the beam height， the vortex response of the streamlined box girder is the largest. On this basis， appropriately reducing or increasing the railing height has a certain vibration suppression effect， and especially reducing the railing height shows a better effect. The research results provide a basis and reference for the design and related research of streamlined box girder railings.