Combined　tension-torsion　fatigue　tests　were　conducted　on　nickel-based　alloy　GH4169　under　proportional　and　nonproportional　loading　at　650　degrees　C.　The　fatigue　cracks　on　the　specimen　surface　were　found　basically　initiating　and　propagating　along　the　maximum　shear　plane.　Taking　into　account　the　materials　in　elastic-plastic　state　under　low-cycle　fatigue,　a　multiaxial　fatigue　damage　parameter　based　on　SW　model　was　proposed.　The　developed　damage　model　can　be　reduced　to　the　uniaxial　Manson-Coffin　equation,　which　was　used　to　evaluate　the　low　cycle　multiaxial　fatigue　for　GH4169　alloy,　Haynes188　and　mild　steel.　It　is　concluded　that　the　predicted　results　with　the　proposed　model　can　give　satisfied　results.　(C)　2009　Elsevier　Ltd.　All　rights　reserved.