Abstract: TC16 titanium alloy was treated by solution at two-phase region temperature (840, 860 ℃) and single-phase region temperature (880 ℃) for 2 h, and then aging at 560 ℃ for 8 h. The effects of solution temperature on the microstructure, phase composition and impact toughness of alloy in the solution state and in the aging state were studied. The results show that the microstructure of TC16 titanium alloy after solution was mainly composed of α phase and α" phase, and after aging was mainly composed of α phase and β phase. With the increase of solution temperature, the content of primary α phase in the soluted alloy decreased, the equiaxialization degree increased, and the content of acicular α phase and α" phase increased. When the solution temperature increased to 880 ℃, the primary α phase disappeared completely. After aging, a large number of needle-like secondary α phase was formed in the microstructure, and the content of secondary α phase increased with the increase of solution temperature, while the content and size of primary α phases had no obvious change compared with those in the solution state. With the increase of solution temperature, the impact absorbed energy and impact toughness value of the alloy after solution increased. After aging, both of them decreased comparing with those in solution state, and decreased with the increase of solution temperature. With the increase of solution temperature, the number of dimples in the impact fracture decreased. When the solution temperature was 880 ℃, the impact fracture was mainly cleavage plane. After aging, more secondary cracks appeared in the fracture. With the increase of solution temperature, the number of secondary cracks increased.