Abstract: This paper focuses on the study of the effects of laser power, welding speed and defocusing amount on the weld bearing capacity during laser lap welding of 1.5mm thickness three-layer X2CrNiN18-7 stainless steel plate.Taking laser power, welding speed and defocusing amount as three factors, a three-factor three-level test was carried out to study the degree of influence of each process parameter on the welding quality, taking weld bearing load,weld depth of fusion, weld surface fusion width and fusion width of the weld lap joint as the indexes. The results show that laser power and welding speed, the amount of focus on the ability of the weld to withstand the load of the influence are relatively large, the specific laser power ＞ welding speed ＞ focus, for the weld melt width, the degree of influence in the following order: the amount of focus ＞ welding speed ＞ laser power.