With different proportions of nitrogen-argon hybrid shielding gas, the experiment of CO₂ laser welding of 2 mm thick SUS301L austenite stainless steel is conducted. The microstructure, comprehensive mechanical, and surface corrosion-resistance properties under different proportions of nitrogen shielding gases are investigated. Experimental results indicated that, under different proportions of nitrogen shielding gases, the micro-morphologies of weld joints have no obvious difference, the nitrogen contents are the same as that of steel substrate, and the phase components are all γ-austenite with combination of a small amount of δ-ferrite; the tensile strength, bend strength, and micro-hardness of weld joints are comparable with that of steel substrate; the weld joint under the shielding of Ar gas possesses the best corrosion resistance property; with the increment of nitrogen content in shielding gas, corrosion resistance of weld joint surface gradually decreases, but the corrosion rate shows a lowering trend.