Thermo-mechanical processing parameters of Ti-43Al-5Nb-0.03Y (mole fraction, %) alloy are investigated by hot simulation tests at 1050~1250 ℃ on Gleeble-1500D with a nominal deformation of 50% and a strain rate of 10-1~10-3?s-1. The true strain–true stress curves have been obtained and the microstructures are observed. The results show that the microstructure consists of recrystallized grains and remained-lamellar when the compression temperature is lower than 1200 ℃, and of recrystallized grains at 1200 ℃. The major mechanism of plastic deformation is the slip deformation and twinning deformation, and the main softening mechanism is dynamic the recrystallization and dynamic recovery in the γ phase. The crack-free pancakes are obtained at a hot compressive temperature of 1200 ℃ and a strain rate of 10-3 s-1.