The invention discloses a method for realizing swing welding with a laser-GMA electric arc hybrid welding device, relating to a laser-melting electrode gas metal arc welding hybrid welding method. The method solves the problem that the defects such as incomplete fusion, gas hole and included slag, and the like, are easily existed between a side wall and a layer when welding a moderate plate and a thick plate with the laser-GMA electric arc hybrid welding device. The method comprises the following steps of: 1. chamfering; 2. clamping a work piece to be welded; 3. ensuring the positions of an electric arc and a laser beam, wherein the laser beam is perpendicularly irradiated to the surface of the work piece to be welded, an included angle between the electric arc and the laser beam is 15-60 DEG C, and the distance between the laser beam and the sharp end of a GMA electric arc welding wire is 2-6mm; 4. setting a welding technology parameter; and 5. performing the welding, wherein an electric arc welding gun is kept to be immovable when welding, and a laser beam-focused wielding gun swinging welds in the shape of 'S'. The method is used for butt welding of a thick plate more than 10mm in national defense and civil use fields of shipbuilding, petroleum pipe lines, high-pressure vessels, fighting vehicles and nuclear devices, etc.