Abstract: Laser melting tests of the surface of AZ31 magnesium alloy FSW joint were carried out by using different laser scanning speed in the range of 1200-1800 mm/min. The effects of the laser scanning speed on the microstructure, tensile strength and corrosion resistance of FSW joint of AZ31 magnesium alloy were explored with the help of optical microscope,universal testing machine, electrochemical workstation and scanning electron microscope. The results show that as the laser scanning speed increases, the depth of the melting layer decreases, the grain size of the melting layer and the heat affected zone is refined, and the content of the β-Mg₁₇Al₁₂ phase increases. After laser melting treatment, the tensile strength of the joint is higher than that of the FSW sample, and the tensile stnength increases with the increase of the laser scanning speed. The corrosion resistance of the welded joint after laser melting treatment is better than that of FSW sample, and when the scanning speed is 1200 mm/min, the corrosion current density of the sample is the lowest, and the corrosion resistance is the best.