Abstract:TC10 titanium alloy was annealed by different processes. The relationship between microstructure and impact properties of the alloy after different annealing processes was studied by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM) and impact property test. The results showed that: After single annealing treatment, the microstructure is composed of primary α phase (αp) and secondary α phase (αs). It is confirmed that no α" phase and α" phase are precipitated. After double annealing treatment, αp phase is almost unchanged, and αs phase is transformed into coarse lamellar αs phase and fine lamellar αs phase. The impact property of the alloy after single annealing is higher than that after double annealing, and the impact property after heating in two-phase region is higher than that in single-phase region. In the two annealing processes, when the heating temperature is two-phase region, the fracture morphology is mainly composed of equiaxed dimples. When the heating temperature is single-phase region, the fracture morphology is dominated by rock-like morphology. And there are shallow small dimples distributed on the surface.