Abstract: By taking 10Ni5CrMoV high strength steel plate as the research object,the influences of the swing path,swing amplitude and swing frequency of laser swing welding on the weld formation and porosity were studied. It is found that the porosity of several kinds in laser swing weld is lower than that of laser non-swing welding. With the increase of frequency,the melting width is basically unchanged and the melting depth is slightly increased in the range of 30 ～ 90 Hz under the vertical swing trajectory. When the swing frequency is within the range of 90 ～150 Hz,with the increase of the swing frequency,the melting width decreases,and the melting depth increases. At the swing amplitude of 2 mm and the swing frequency in 30 ～ 60 Hz,the porosity of the weld seam is relatively low,and the porosity is lower than 0. 15%.