Traditional　modeling　approaches　are　difficult　to　reflect　the　slight　changes　of　bridge　system　parameters　and　responses.　Due　to　this，digital　twins　are　adopted　as　the　high　fidelity　mapping　models　for　a　bridge　system.　Firstly，the　definition　of　digital　twins　comprises　three　parts　of　a　physical　twin　layer，a　digital　twin　layer　and　an　information　interaction　medium.　The　digital　twin　model　inside　the　digital　twin　layer　is　the　virtual　mapping　of　the　bridge　physical　entity，and　the　real-time　information　transmission　between　the　two　layers　is　achieved　by　the　information　interaction　medium.　Secondly，in　view　of　practical　applications，three　modeling　principles　of　structural　informatization，information　digitization　and　data　modelization　are　proposed　to　realize　the　informatization　and　visualization　of　the　bridge　physical　entity.　Thereby，the　digital　twin　model　with　high　fidelity　is　established　for　the　cable-stayed　bridge.　Lastly，the　monitoring　data　of　a　back-stay　cable　of　an　actual　bridge　are　adopted　as　the　perceptual　information，and　the　changed　cable　parameters　are　fed　to　the　digital　twin　model　for　twin　model　updating　and　response　prediction.　The　analyses　results　demonstrate　that　the　proposed　digital　twin　modeling　method　can　effectively　reflect　the　parameter　changes　of　the　actual　bridge.　Then　the　corresponding　slight　variations　of　the　cable　force，the　tower　top　deviation　and　the　mid-span　deflection　of　the　main　girder　are　predicted　by　the　twin　model.　©　2024　Nanjing　University　of　Aeronautics　an　Astronautics.　All　rights　reserved.