[show abstract][hide abstract] ABSTRACT: The influences of rare earth metal (Y) on microstructure, mechanical properties and deformability of Ti–43A1–9V alloy are reported. The results show that Ti–43Al–9V–0.3Y alloy is composed of γ, α2, B2 and YAl2 phases. Adding 0.3at.% Y refines the grain size, decreases α2/γ/B2 lamellar thickness of Ti–43Al–9V alloy, and promotes the formation of fine α2/γ lamellae. Mechanical property tests show that adding 0.3at.% Y can apparently enhance strength and plastic property of Ti–43Al–9V alloy. The hot deformation experiment at 1200 °C indicates that adding 0.3at.% Y can improve deformability of Ti–43Al–9V alloy, because Ti–43Al–9V–0.3Y alloy has smaller grain size, lower resistance to deformation, and fine and uniform recrystallized grains.