Abstract: To reduce welding distortion,arc spot welding was used to join 3 mm and 5 mm thick 0Cr18Ni9 stainless steel sheets. Effects of three section welding current on weld penetration,nugget diameter and shear resistance of joints were mainly investigated. The research results showed that weld penetration,nugget diameter and shear resistance of joints increased with the increase of the first current and the second current. The first current mainly affected on weld penetration,while the second current mainly affected on both weld penetration and nugget diameter,especially nugget diameter. However,the third current did not affect weld penetration or nugget diameter,which mainly affected on formation of weld. Optimizing the first welding current and second welding current and their relevant parameter could improve the shear strength of arc spot welded joints.