Abstract: Taking a three-span prestressed concrete continuous box girder bridge as a research object， the vehicle and bridge differential equations of motion of single beam were established using vehicle-bridge coupling vibration relationship which was built through compatible relationship of deformation and force between vehicle and bridge． Using the WIM system installed on bridge， the actual traffic load moving on bridge was efficiently identified，which was taken as vehicle load information inputting into updated self-developed bridge dynamic response calculation program． The bridge dynamic response under actual vehicle load can be calculated by the program quickly， and the calculation result has been verified statically and dynamic verification has been done using ANSYS software and bridge dynamic strain response under actual traffic flow， respectively．