Experimental studies are conducted on welding of 08 Ni3 DR steel developed by one steel mill. According to the determined welding technology and parameters,mechanical properties of welded joints of 08 Ni3 DR steels welded by SMAW and SAW respectively,such as tensile,series impact and other properties are systematically studied. The results show that welded joints of 08 Ni3 DR steel have excellent comprehensive mechanical properties,and can meet the design requirements of pressure vessel which applied in temperature not lower than-100 ℃.