In　this　paper,　the　competition　mechanism　between　protectiveness　and　harmfulness　of　oxidation,　as　well　as　the　effects　of　cycle　period,　mean　stress　and　temperature　on　the　damage　behavior　of　TA15　titanium　alloy　are　revealed　under　multiaxial　thermo-mechanical　fatigue　loading.　Based　on　the　damage　mechanism,　a　high-temperature　environmental　damage　model　is　proposed　under　multiaxial　thermo-mechanical　fatigue　loading　first,　then　a　life　prediction　method　is　developed　by　combining　a　multiaxial　fatigue　damage　model.　The　experimental　verification　results　under　uniaxial　and　multiaxial　thermo-mechanical　fatigue　loadings　showed　that　almost　all　of　the　prediction　errors　are　within　a　factor　of　2.