The　excellent　performance　of　the　CFRP-concrete　bonding　interface　is　a　key　to　ensure　the　reliability　and　effectiveness　of　the　rehabilitation　in　concrete　structures　with　external　fiber　reinforced　polymer　(FRP).　Meanwhile,　the　epoxy　primer,　which　bonded　the　FRP　plate　and　the　concrete　substrate,　is　significantly　affected　by　the　aggressive　environment.　In　this　paper,　two　kinds　of　experiments　which　associated　with　the　CFRP-concrete　specimens　and　the　epoxy　primer　after　corroding　in　a　wet-dry　cycles　environment　were　conducted.　It　shows　that　the　immersion　area　of　the　epoxy　primer　has　a　significant　influence　on　the　properties　of　the　moisture　absorption,　and　that　would　lead　to　a　degradation　in　the　mechanical　properties　of　the　CFRP-concrete　interface.　Simultaneously,　the　failure　modes　of　the　CFRP-concrete　interface　presented　a　transformation　from　the　epoxy/concrete　interaction　layer　to　the　epoxy　primer　layer　along　with　the　increase　of　aging　duration.　To　further　depict　the　degraded　bond　behavior,　a　time-dependent　bond-slip　model　considering　the　degradation　of　epoxy　primer　was　proposed,　and　the　interface　fracture　energy　was　utilized　to　quantify　the　degree　of　the　deterioration.　By　comparing　with　the　value　of　interface　fracture　energy,　it　was　figured　out　that　the　normal　bond-slip　model　(Popovics　model)　is　not　enough　for　the　safety　of　the　concrete　structures　rehabilitated　with　external　CFRP,　and　the　proposed　time-dependent　bond-slip　model　is　more　accurate　in　evaluating　the　time-dependent　mechanical　properties　of　concrete　structures　suffering　in　an　aggressive　environment.　©　2021　Elsevier　Ltd