Abstract: In order to reasonably predict the distribution law of fan noise in the longitudinal ventilation of urban tunnels and provide reference for the feasibility study of longitudinal jet ventilation of urban pedestrian tunnels, two typical urban tunnels are selected to conduct field test of the noise under the condition of longitudinal ventilation in the tunnel, the noise distributions in the tunnel with single and multiple groups of fans are analyzed, and the noise control standards for the pedestrian tunnel are given. The results show that: the noise in the tunnel is mainly the medium and low frequency noise when the fans are not running, and the highest noise level is concentrated between 1 000-2 000 Hz, noise frequency of the fan is mainly concentrated between 250-4 000 Hz, and the highest noise level is concentrated between 500-2 000 Hz; the fan noise shows a basically linear attenuation tendency in the tunnel when a single group of jet fan is running; when multiple groups of jet fans are running, the distribution pattern of noise level between two groups of fans is symmetric with characteristics of being high on two ends and low in the middle along the longitudinal direction, the noise level is higher compared with that of single group of jet fan, the average noise increment is about 4 dB(A); the noise control standard for the urban pedestrian tunnel is that the noise level at 1.5 m above the ground should not be higher than 65 dB(A), and it is suggested that full jet ventilation mode should not be adopted in urban pedestrian tunnels