The　characteristics　of　strains　on　the　maximum　shear　plane　were　analyzed　under　tension-torsion　multiaxial　fatigue　loading.　The　critical　damage　planes　were　determined　by　the　critical　plane　principle　under　different　loading　parameters.　On　the　basis　of　the　uniaxial　fatigue　constants　at　high　temperature,　a　multiaxial　fatigue　damage　parameter　was　proposed　to　calculate　the　pure　fatigue　damage.　The　half　of　maximum　equivalent　amplitude　is　used　as　the　creep　stress　to　calculate　creep　damage.　Hence,　a　linear　multiaxial　creep-fatigue　life　prediction　model　was　proposed　to　predict　the　creep-fatigue　life　at　high　temperature.　The　multiaxial　fatigue　data　for　thin　tubular　specimens　made　by　a　high　superalloy　GH4169　were　used　to　verify　the　proposed　multiaxial　fatigue　life　prediction　model　under　proportional　and　non-proportional　loading　at　high　temperature.　The　results　have　shown　that　the　proposed　multiaxial　fatigue　life　prediction　model　can　accurately　predict　multiaxial　creep-fatigue　life　at　high　temperature.　The　error　is　within　a　factor　of　2.