Abstract: Mass loss and galvanic corrosion tests were used to investigate the corrosion behavior of the 316 L/625 composite tube in seawater. The results showed that the mean corrosion rate of the 316 L and 625 alloy were less than 0.01 mm/a after 3 months of immersion, and the corrosion rate of the welding joint was 0.015 mm/a. The 316 L stainless steel was not sensitive to galvanic corrosion, the galvanic corrosion factor was less than 130%.