Abstract: ［Objective］ It is aimed to investigate the relationship between the welding deformation degree of aluminum alloy materials and the welding methods, with the purpose of exploring the effects of different welding processes on aluminum alloy welding deformation. ［Method］ By comparing the weldability of CMT (cold metal transfer) welding technology with that of MIG (metal inert gas) welding, the characteristics and applications of the CMT welding process are discussed in detail. During the experiment, aluminum plates with thicknesses of 3 mm and 8 mm are welded using CMT and MIG welding processes respectively, and each resulting welding deformation is observed and recorded. ［Result & Conclusion］ For 3 mm thick aluminum plates, only minimal deformation is observed after CMT welding, whereas MIG welding led to significant welding deformation of 4 mm. For 8 mm thick aluminum plates, although both welding methods result in some deformation, the deformation with CMT welding is notably less than that with MIG welding. Additionally, both CMT and MIG welding processes produce uniform and aesthetically pleasing welds, with a weld penetration depth of 0.5 mm and showing no significant difference between the two. Consequently, the CMT welding process has a significant advantage in controlling welding deformation of aluminum alloys, making it suitable for welding aluminum alloy components that require strict control over deformation.