Abstract: The 7A52 aluminum alloys of 40mm in thickness were welded by using Twin-wire gas shielded arc welding (DWGSAW) with ER5356 filler, and the microstructure of the weld seam was analyzed.Meanwhile, according to the actual application environment, the base metal and the weld seam were studied in 3.5% NaCl solution after welding.Results show that the microstructure of the seam welded by DWGSAW is composed of α(Al)+β(MgZn₂), which the crystal grain is compact and petty, and the center of the weld is equiaxed grain.The corrosion resistance of 7A52 aluminum alloy is liable to pitting corrosion in humid environment containing chloride iron.However, a thin and condense aluminum oxide film is formed on the corroded surface, which is beneficial to increasing the corrosion resistance of the 7A52 aluminum alloy.The corrosion resistance of the weld seam is better and the pitting corrosion is rare on the corroded surface.