In order to study the influence of bridge deck railing on the vortex-induced vibration performance of main beams, a domestic scenic pedestrian suspension bridge with wide-span ratio of 0.028 4 was taken as the engineering background, and the vortex-induced vibration response characteristics of main beams with and without railings were analyzed and calculated by CFD numerical simulation me-thod. The effects of the railing form and different air permeability on the vortex-induced vibration charac-teristics of the main beam are analyzed and summarized. On this basis, the influence mechanism of vortex stripping on the vortex-induced vibration performance of the main beam is revealed from the evolution form of vortex stripping and the distribution of wind pressure coefficient. The results show that the maximum vortex-induced vibration amplitude of the main beam with railings is 2.2 times that of the main beam without railings. Increasing the railing radia will increase the vortex-induced vibration amplitude of the main beam, but increasing the air permeability of the railing can effectively reduce the vortex-induced vibration amplitude of the main beam. Compared with those without railings, the vortices formed on the upper surface of the main beam with railings are larger in scale and more in number, and the curves of the average wind pressure coefficient and the fluctuating wind pressure coefficient both fluctuate greatly, which explains the reason for the increase of the vortex-induced vibration amplitude of the main beam after the railings are set up to a certain extent.