This　paper　presents　a　thermo-mechanical　fatigue　(TMF)　life　prediction　method　for　titanium　alloy　TA15　under　multiaxial　random　amplitude　loading.　Through　strain-controlled　TMF　tests,　it　was　found　that　under　full-reversed　cyclic　loading,　there　was　a　significant　presence　of　mean　stress　in　the　stress　response.　The　induced　mean　stress　led　to　the　anomalous　phenomenon　where　the　fatigue　life　of　thermal　phase　angle　out-of-phase　(TOP)　was　shorter　than　that　of　thermal　phase　angle　in-phase　(TIP).　Therefore,　a　new　damage　calculation　model　was　proposed,　which　can　take　into　account　the　pure　fatigue　damage　considering　mean　stress　conversion　and　the　cumulative　environmental　damage.　Uniaxial　TMF　tests,　constant　amplitude　multiaxial　TMF　tests,　and　random　amplitude　multiaxial　TMF　tests　are　conducted　to　verify　the　proposed　method.　The　predicted　results　for　all　types　of　tests　are　in　a　good　agreement　with　the　experimental　data.