Isothermal　constant　strain　rate　compression　testing　of　a　new　as-cast　high-temperature　titanium　alloy　Ti-6.5Al-11.5(Sn,Zr)-2.5(Mo,W,Nb)-0.25Si-0.1Er　was　carried　out　at　the　deformation　temperatures　range　from　900°C　to　1100°C,　strain　rate　range　from　0.001　to　1　s-1　and　60%　of　engineering　strain.　The　deformation　behavior　of　this　high-temperature　titanium　alloy　was　analyzed　based　on　the　stress-strain　result,　and　the　constitutive　equation　based　on　the　hyperbolic　sine　model　and　the　parameters　of　Zener-Hollomon　was　established,　showing　a　close　accordance　with　the　experimental　value.　The　hot　processing　maps　based　on　the　dynamic　material　model　and　the　Prasad’s　instability　criterion　were　constructed　at　strains　of　0.3　and　0.6.　The　maps　exhibit　two　stable　deformation　domains　in　the　temperature　range　of　940~960°C　and　strain　rate　range　of　0.001~0.002s-1,　and　in　the　temperature　range　of　1030~1070°C　and　strain　rate　range　of　0.02~0.06s-1　with　the　power　dissipation　efficiency　of　58.5%　and　54.5%,　respectively.　©　2017　Trans　Tech　Publications,　Switzerland.