Laser welding with filler wire and MIG welding are used for lap fillet weld of SUS301L stainless steel,and the differences of appearance of weld between these two welding methods are compared. The welding simulation of two welding methods is carried out by using Simufact. Welding software.The calculated molten pool shape is basically consistent with the experimental results. The temperature field,stress field and deformation under different welding methods are analyzed.Both laser welding and MIG welding are rapid heating and cooling processes,but the heat input of MIG welding is relatively large and the cooling rate is relatively slow comparing with laser welding. Larger effective stress exists in the heat affected zone of welds obtained by these two welding methods. The workpieces obtained by these two welding methods deform after complete cooling,and the deformation of MIG welding is large.