To study the comfort level of human-induced vibration of a variable section steel-truss pedestrian bridge and the vibration reduction effect of tuned mass damper (TMD), a steel truss girder pedestrian bridge on the Beijing Hangzhou Grand Canal was taken as the research object. Finite element simulation and on-site measurement were used to study the human-induced vibration response of the steel truss pedestrian bridge. Based on the finite element model, the vibration response of the bridge before installation of TMD was analyzed, the pedestrian comfort level was determined, and the influence of pedestrian density, damping ratio and crowd excitation frequency on the bridge was discussed. In this way, the TMD design parameters were given, and the influence of TMD mass ratio on the vibration reduction effect was analyzed. On site measurements were conducted on the pedestrian bridge after the installation of TMD, and based on which acceleration time history and frequency spectrum analysis were used to study the human-induced vibration response of the bridge under corresponding operating conditions. Comparison of the results shows that before installing the TMD, the acceleration response of the bridge exceeds the specification limit, and the effect of human-induced vibration should be considered. In a certain range, the acceleration response increases with the increase of pedestrian density and decreases with the increase of damping ratio. The vibration response increases significantly when the pedestrian step frequency is close to a certain order of the vibration frequency of the bridge. After the installation of TMD, the measured human-induced vibration response of the bridge is reduced, and its response is consistent with the simulation results. The research results in this paper can provide theoretical support for the study of human-induced vibration of variable section steel truss bridge.