Abstract: The tensile properties,Charpy V-notch impact energy and fracture toughness of 2.25Cr-1Mo steel,which was used in piping elbow of hydrogenation reactor for 200 000 h,were tested at cryogenic temperature. Based on these tests,the master curve reference temperature T0 of the steel was obtained,and the fracture toughness distribution in the whole ductile-brittle transition temperature zones was got. The results show that the master curve reference temperature of 2.25Cr-1Mo steel was -154 ℃,the material of elbow still had good toughness after 200 000 h service. The applicability of Master Curve method to 2.25Cr-1Mo steel which is not used in nuclear power is validated.