The　fatigue　weak　area　of　aluminum　alloy　for　a　friction　stir-welded　joint　is　investigated　based　on　the　hardness　profile,　the　residual　stress　measurement　and　the　simulation　analysis　of　fatigue　property.　The　maximum　residual　stresses　appeared　at　the　heat-affected　zone　of　the　joint　in　the　fatigue　damage　process,　which　was　consistent　with　the　fracture　location　of　the　fatigue　specimen.　The　fatigue　joint　model　of　continuous　performance　is　established　ignoring　the　original　negative　residual　stress;　considering　that　it　will　be　relaxed　soon　when　the　joint　is　under　tension-tension　cyclic　loading.　The　fatigue　parameters　of　joint　model　is　based　on　the　static　mechanical　properties　of　the　joint　that　obtained　from　the　micro-tensile　tests　and　four-point　correlation　method.　The　predicted　results　for　the　fatigue　weak　locations　and　fatigue　lives　based　on　the　continuous　performance　joint　model　are　closer　to　the　fatigue　experimental　results　by　comparison　with　the　simulation　results　of　the　partitioned　performance　joint　model.