Abstract: The large-sized Ti-43Al-9V-Y alloy pie with duplex (DP) structure was produced by vacuum consumable electrode arc furnace remelting, homogenizing treatment, hot isostatic pressure and hot-pack forging process, and the fully lamellar (FL) structure was obtained after the pie was treated at 1 350 ℃ for 8 h, Tensile properties of the alloy with DP and FL structure at different positions were performed at room temperature, 700, 750, 800 and 900 ℃. The fracture morphology of tensile samples were observed. The results show that, the tensile properties of different position of DP structure were nearly the same owing to uniform microstructure. From room temperature to 700 ℃, the yield strength decreased slightly and kept a high level. From 700 ℃ to 900 ℃, the yield strength decreased rapidly with the increase of temperature. At 700 ℃, the average elongation of the alloys with DP structure and FL structure were 8.3% and 2.05%. When temperature was over 700 ℃, the alloys showed softening trend. Dimples and apparent oxidizing coating were found on tensile fracture surfaces at 800 ℃.