The invention belongs to the technical field of welding, and provides a braze-welding method for thin-wall stainless steel leakage holes. The method comprises the following steps: clearing the peripheries of the leakage holes; connecting ground wires; adopting argon gas to protect back surfaces of the leakage holes; regulating welding current of an argon-arc welding gun; putting welding wires above front surface of the leakage holes, and enabling end parts of the welding wires to be in good contact with thin-wall stainless steel of the leakage holes; striking arcs on the welding wires by the argon-arc welding gun, and moving electric arcs to the end parts along the welding wires after striking the arcs; melting the end parts of the welding wires to form molten drops, and dropping the molten drops to positions of the leakage holes to cover the leakage holes; and continuously heating the molten drops by the argon-arc welding gun to enable the molten drops to completely welded with parent materials of the leakage holes. The invention provides a novel braze-welding process, wherein high-melting-point welding wires can be applied to braze-welding, so that fusion repair welding of thin-wall stainless steel leakage holes is realized. The method is very suitable for maintaining equipment, so that indirect economic benefit potential is great.