Nanosecond pulse laser was used to lap weld 316 stainless steel with 0.2 mm thickness, then was used to scan modified the appearance of spots. Through orthogonal experiment for laser scanning process parameters, it was known that when laser power was 25 W, pulse frequency was 600 kHz, scaning speed was 1 500 mm/s, residual height of spots was 28.7 μm, and appearance of spots were not yellowing and blackening, which met requirements of production. Cross section analyzed results showed that after laser scanning, oxide layer produced during welding was removed, residual height of spots was decreased, and appearance was been changed to no yellow, no black.