The invention discloses a method for welding dissimilar metals of copper and steel. The method comprises the following steps that a heating end part of heat supply equipment is protected under inert gas, contact surfaces of two materials of the copper and the steel are heated, the temperature is controlled to rise continuously, the heating end part of the heat supply equipment is controlled to shift towards the direction of the copper material, the distance between offset distance and a contact surface is 0.2 mm-0.3 mm, the temperature is increased to 1050-1350 DEG C, the to-be-welded ends ofthe two materials of the copper and the steel are continuously melted to form a copper-steel liquid-state molten pool, the to-be-welded ends of the copper and the steel are mutually interfused to forma weld joint, the weld joint is cooled to the normal temperature to complete the welding. According to the method, during welding, tungsten electrode serves as an electrode to melt the copper steel material, and a liquid molten pool is gradually formed on a welding contact surface; the copper material and the steel material can be mutually and completely interfused, meanwhile, the stable weldingform meets the welding penetration requirement, and the weld joint is full and capable of forming surface tension as well; the surface shape of the weld joint of the copper material and the steel material is in a convex non-linear arc shape and is not a straight shape, and the welding strength can be improved.