A wind-vehicle-bridge system can be regarded as an interaction result of wind-bridge interaction,wind-vehicle interaction and vehicle-bridge interaction,which is determined by nature wind,dynamic characteristics of vehicle and bridge structures,interrelationship between bridge and vehicle dynamic properties and so on.Firstly,based on the traffic loading investigation on the expressway bridge within 24 hours a day,all the critical parameters of traffic flow,such as the vehicle type,weight,separation space and speed are all recorded and analyzed to extract its statistical characteristics,which are used to work out random traffic flow simulation program RTF.This RTF program can be embedded with the other general FEM software.Secondly,a dynamic analysis module RTFWVB of the wind-vehicle-bridge coupling vibration under random traffic flow is presented,which can consider arbitrary number of vehicles,multi-lanes and traffic flow direction.Finally,Hangzhou Bay Bridge in China is selected as a numerical example to demonstrate dynamic interaction of the RTFWVB system.The results indicate that the traffic flow direction has just a little influence on bridge dynamic response,that the mean responses are mainly determined by the moving vehicle loads,and that the fluctuating components will increase with the increase of wind speed. Wind-vehicle interaction and vehicle-bridge interaction, which is determined by nature wind, dynamic characteristics of vehicle and bridge structures, interrelationship between bridge and vehicle dynamic properties and so on. Firstly, based on the traffic loading investigation on the expressway bridge within 24 hours a day, all the critical parameters of traffic flow, such as the vehicle type, weight, separation space and speed are all recorded and analyzed to extract its statistical characteristics, which are used to work out random traffic flow simulation program RTF. This RTF program can be embedded with the other general FEM software. Secondarily, a dynamic analysis module RTFWVB of the wind-vehicle-bridge coupling vibration under random traffic flow is presented, which can consider arbitrary number of vehicles, multi-lanes and traffic flow direction .Finally, Hangzhou Bay Bridge in China is selected as a numerical example to demonstrate dynamic interaction of the RTFWVB system. The results indicate that the traffic flow direction has just a little influence on bridge dynamic response, that the mean responses are mainly determined by the moving vehicle loads, and that the fluctuating components will increase with the increase of wind speed