The invention relates to a tool and a method for spot-welding loose wires of a frame of a loudspeaker. The tool comprises a tool base plate; a notch which is sunk towards the middle of the tool base plate is arranged on one side of the tool base plate; a supporting portion is arranged on the tool base plate and is positioned below the notch; a limiting portion which is matched with the supporting portion is arranged on the tool base plate and above the notch; limiting space is formed among the supporting portion, the limiting portion and the wall of the notch; a wire crossing block is arranged on the upper end surface of the tool base plate and is positioned on one side of the center of the wall of the notch; one end of the wire crossing block extends to the middle of the notch; and a wire crossing groove opening is arranged at the extending end of the wire crossing block. Wires welded by the tool and the method are loose, and the phenomenon that the wires are pulled manually, are quite tight and even can be broken is avoided. In addition, because the wires cannot be tight, the anti-impact ability of welding points of the wires is increased, the quality of products is improved, and risks of customer complaint are reduced.