Abstract: The microstructure of TA31 alloy treated by different low-temperature aging processes is analyzed. Tensile and charpy impact tests are carried out to find out the effects of different low-temperature aging processes on the strength, plasticity, impact toughness and fracture morphology of TA31 titanium alloy. The results show that after low temperature aging, acicular martensite αˊ and metastable β phases in solid solution TA31 alloy are broken down into dispersive stable α+β phases, which improves the strength of TA31 titanium alloy. The percentage elongations after fracture and percentage reductions of area of TA31 titanium alloys in annealed, quenched and aged states have no variations, and all of them have good plasticity. The impact toughness of as-annealed TA31 alloy is the highest, which decreases after solution at 940℃, and does not change significantly after aging at 650℃.