The tensile tests of Ti-3Al-2.5V (TA18) tubes with the diameter of 16 mm by cold rolling were accomplished on an electro-hydraulic servo material testing machine at –60, 25, 100, 200, 300 and 350 oC, respectively. Meanwhile, microstructure of TA18 titanium alloy tubes after fracture was observed by TEM when tests were carried out at different temperatures. The results indicate that the tensile strength and the elongation of TA18 titanium alloy tubes decreases with the rise of temperature. There is a large amount of mechanical twins in the specimens deformed at –60 oC, but they don’t exist at 350 oC. It is concluded that twinning plays an important role in the process of TA18 titanium alloy tubing deformation.