Abstract: Swing welding technology was employed to weld ordinary low carbon steel with 3 mm in thickness, and the influence of swing welding parameters on weld appearance had been studied, and three sets of welds with different weld widths had been designed and implemented. Experimental results showed that, the influence of welding mode on weld shape was not obvious. As the length of the cycle increased, the gap in the horizontal direction of the weld increased gradually, an appropriate increasing in the width of the swing cycle would increase the width of the weld and the swing pause length should be controlled within 4 mm or less, otherwise there would be weld collapse phenomenon. There was no occurrence of weld collapse, layer fusion and undercut phenomenon on 3 group wide seam welding parameters, which met the requirements of wide welding seam welding.