To　evaluate　the　fatigue　life　of　RC　structures　in　a　marine　or　deicing　environment,　the　effects　of　the　fatigue　load　level　(ratio　of　the　maximum　fatigue　load　to　the　static　ultimate　strength),　initial　fatigue　loading　cycles,　chloride　exposure　duration　and　reinforcement　ratio　were　taken　into　consideration.　The　corrosion　initiation　time　of　fatigue-damaged　RC　beams　under　a　two-dimensional　chloride　diffusion　state　was　calculated　based　on　Fick’s　Second　law,　and　the　relationship　between　the　residual　fatigue　life　and　corrosion　initiation　time　was　analyzed.　The　fatigue　life　prediction　model　of　fatigue-damaged　RC　beams　after　chloride　corrosion　was　proposed,　and　then　suggestions　for　the　fatigue　durability　design　and　evaluation　were　given.　The　results　show　that　the　fatigue　load　level　(no　less　than　0.　4),　initial　fatigue　loading　cycles　(no　more　than　0.　4　million)　and　chloride　corrosion　exposure　duration　have　significant　influences　on　the　corrosion　initiation　time,　while　the　initial　fatigue　loading　cycles　(0.　4-1.　2　million)　and　the　reinforcement　ratio　hardly　affect　it.　The　corrosion　initiation　time　is　exponentially　correlated　with　the　residual　fatigue　life,　based　on　which　a　fatigue　life　prediction　model　is　proposed,　which　is　in　good　agreement　with　the　test　value.　This　model　is　based　on　the　diffusion　of　chloride　ions　in　concrete,　which　is　applicable　for　the　fatigue　life　evaluation　of　in-service　RC　bridges.　The　durability　of　RC　bridges　in　areas　not　directly　in　contact　with　seawater　(e.　g.,　2.　84　km　or　more　from　the　coast)　could　not　be　neglected.　©　2022　Science　Press.　All　rights　reserved.