Based　on　ANSYS　finite　element　analysis　software,　a　dynamic　model　of　the　Beijing-Tianjin　intercity　railway　car-track-bridge　system　is　established　to　analyze　the　dynamic　response　of　the　bridge　under　the　normal　high-speed　double-track　traffic　conditions.　Combined　with　the　statistics　of　actual　train　operation,　the　bridge　load　spectrum　represented　by　wheel/rail　force　is　obtained.　With　the　aid　of　the　rain-flow　counting　method,　the　stress　data　of　the　weak　part　of　the　bridge　span　is　equivalently　converted　into　variable　amplitude　stress　amplitude　and　the　corresponding　cycle　times　are　obtained.　In　this　way,　the　stress　spectrum　of　the　Beijing-Tianjin　intercity　railway　bridge　in　the　use　reference　period　is　estimated,　which　provides　a　certain　reference　basis　for　the　life　assessment　of　the　in-service　bridge　and　the　reinforcement　of　weak　parts　in　the　future.　©　Published　under　licence　by　IOP　Publishing　Ltd.