Abstract: With the development of high-nitrogen steel in the field of marine engineering, the performance requirements for its welded joints are becoming increasingly stringent. This paper employs a semiconductor laser to weld high-nitrogen austenitic stainless steel with a nitrogen content of 0.7%, investigating the microstructure, elemental changes, and corrosion resistance of the welded joints under different laser power conditions. The results indicate that as laser power increases, the penetration depth and width of the weld increase, the number of dendritic crystal structures in the weld increases, and the nitrogen content in the weld decreases with increasing laser power, forming compounds such as carbides and nitrides. At a laser power of 2300 W, the bending strength of the joint reached a maximum of 4346.5 N, accounting for approximately 92.7% of the base material. The hardness of the joint was lower than that of the base material, with little difference across different laser powers. Through electrochemical corrosion tests, at a laser power of 1900 W, nitrogen loss is minimal, which is more conducive to the formation of a passivation film. The capacitive arc radius is maximum, and the corrosion current is minimum, resulting in better pitting corrosion resistance of the welded joint.