The effect of annealing temperature on microstructure and mechanical properties of Ti-6 Al-3 Nb-2 Zr-1 Mo alloy was studied. The results show that with the increase of annealing temperature, the content of primary α phase decreases, and the small angle grain boundary of 2°～15° decreases gradually. In addition, phase transformation α phase→β phase→α phase occurs during annealing at higher annealing temperature, and the <0001>//transverse texture disappears. With the increase of annealing temperature, the yield strength of Ti-6 Al-3 Nb-2 Zr-1 Mo alloy gradually decreases, while the tensile strength and elongation first increase and then decrease. With the increase of annealing temperature, the proportion of lamellar structure increases, the ratio of crack propagation work to impact energy increases, and the toughness of material increases.