The effects of pre-deformation on the aging behavior and mechanical properties of Ti-6Al-4V alloy were studied. Results show that the addition of pre-deformation after the solution process at 940 °C and 955 °C is beneficial in promoting the precipitation of the secondary α phase during the aging of Ti-6Al-4V alloy. When solution temperature was 940 °C, the content of the secondary α phase increased with an increase in pre-deformation amount, its size decreased, and the strength and hardness of the alloy increased monotonously after aging. The tensile strength and hardness of Ti-6Al-4V alloy after aging were evidently higher with pre-deformation than without pre-deformation. Simultaneously, excellent plasticity was maintained. In the case with added pre-deformation, a solution temperature of 955 °C slightly improved the strength and hardness of Ti-6Al-4V alloy compared with a solution temperature of 940 °C. Scanning electron microscopy examinations indicate that the fracture modes of all aged alloys with varying pre-deformation degrees are ductile fracture.