In order to ensure the enough welding strength and durability of the ship in seawater environment, 5083-O aluminum alloy was used to simulate the corrosion resistance of welded joints in seawater. The effects of laser power, welding current and wire spacing on the corrosion resistance of aluminum alloy welded joints were studied by using the highly adaptable laser-melting inert gas (MIG) shielded welding hybrid welding system. The results show that, the self-corrosion current density increases first, then decreases and then increases with the increase of laser power, and varies in the V-shape with the increase of welding current and wire spacing, that is, it decreases first and then increases. When laser power is 3.0kW, welding current is 200A and wire spacing is 3mm, the microstructures of the joint are mainly equiaxed grains, and the defects such as pores are few. At the same time, the micro-blocking galvanic cell effect of the joint is weak, the self-corrosion current density is minimum, and the corrosion resistance of the joint is relatively good. This study is helpful to understand the defect formation mechanism and improve the corrosion resistance of aluminum alloy welded joints.