In order to study the influence of laser shot peening (LSP) on the corrosion resistance of Mg alloy, some AM50 samples are processed with Ndglass pulsed laser. The experimental results show that plastic deformation occurred in the surface layer, density and hardness are improved, great compressive residual stress is formed, and the residual stress on the surface reaches 146 MPa with laser power density of 3 GW/cm2. The electrochemical polarization results show that the corrosion potential and pitting potential of the LSP sample increase by 64 mV and 92 mV as compared to the untreated sample, respectively, while the corrosion current density decreases about 88.6%. After 20 hours continuous spraying in the salt spray environment, more and larger pits appear on the surface of untreated sample, and the corrosion area is reduced by 84.7% after laser shot peening. The corrosion resistance of AM50 Mg alloy is improved markedly by laser shot peening.