Abstract: The quantitative evaluation of the vibration serviceability problem of pedestrian bridges under different walking speed is studied, and the evaluation results are developed in a probabilistic form. The walking load in different time domains under different walking speed is established, considering the individual variability of pedestrian parameter and population variability of a dynamic load factor. A first-order vertical vibration-based benchmark footbridge under the action of walking loads is selected as the research object according to the suggestion of ?ivanovi?. The acceleration peak value of a pedestrian bridge under different walking speed is obtained by applying the pedestrian load in a random time domain under different walking speed to the benchmark footbridge, and the results are corrected to attain the corresponding probability of each peak value after correction as well as the cumulative probability that is less than or equal to a specific peak value. The results show that: when the walking frequency is consistent with the frequency of a pedestrian bridge, the peak value reaches its maximal value and increases linearly with the increase of waking speed; when the pedestrian walks slowly, the vibration serviceability is the highest; when the pedestrian walks quickly, the vibration serviceability is middle; when the pedestrian walks at an intermediate speed, the vibration serviceability is the lowest.