This　paper　presents　a　long-term　condition　assessment　approach　of　cables　under　in-service　loads　collected　by　SHM　system.　For　the　cables　of　the　bridge,　the　stochastic　axial　force　response　can　be　collected　by　the　SHM　system　and　described　by　a　filtered　Poisson　process,　through　which　the　maximum　value　distribution　of　axial　forces　in　its　design　reference　period　can　be　derived　using　Poisson　Process　theory.　The　long-term　deterioration　process　of　steel　wires　in　the　cables　considers　simultaneously　the　uniform　and　pitting　corrosion　due　to　environmental　attack　and　the　fatigue　propagation　induced　by　cyclic　stress.　By　employing　first　order　reliability　method,　the　reliability　of　the　cables　under　the　monitored　responses　is　further　estimated　in　terms　of　the　safety　under　the　extreme　traffic　load　distribution　in　the　design　reference　period　and　the　serviceability　specified　in　the　design　specification.　The　discussions　of　the　lifecycle　condition　assessment　of　the　cable　stayed　bridge　provide　guidance　to　the　future　decision　making　related　to　maintenance　and　replacement.