The laser welding process of Ni201 sheet with single-sided gas supply and double-sided forming is studied, and the welds are tested and analyzed. The results show that the weld is well-formed, the influence of groove depth on weld width is weak, and the weld zone is coarse austenite structure. The result of stomatal type detection shows that the type of weld porosity is oxygen hole, and the mass fraction of oxygen versus groove depth presents a V typed change. When the groove depth is 3 mm, the oxygen mass fraction of welds is the smallest, the joint strength reaches to 377.7 MPa, which is about 80% of the base metal strength, and the welding parts meet the requirements of use.