Abstract: Three different welding processes of duplex stainless steel S31803 were used to welding test coupon, based on the analysis of micro-structures, tests of mechanical properties, oxygen content and corrosion resistance, the optimal welding parameters were determined, and the effect of different welding process on welding joint were analyzed. The results show that, compared with the joints of GTAW and SMAW, the impact toughness and corrosion resistance of GTAW+SAW welded joint can meet the manufacturing requirements of duplex stainless steel. It can be used widely in manufacturing of pressure vessel.