The present invention provides an improved structure for a battery plug, wherein plug contacts are plugged into a plug socket to supply electric power, which is conducted to conducting wires. Magnets serve as electrical connecting interfaces when the conducting wires are connected to positive and negative poles and electrical contact points of a battery, Moreover, the magnets are each provided with a strong attraction function which is used to prevent the conducting wires from separating from the positive and negative poles of the battery and producing poor contact with electrical contact points of the battery. Furthermore, the magnetic magnets can be freely moved, and are not affected by shape or size of the battery or different positions and spacings of the contact points, thereby enabling the plug device to achieve multifarious electrical connecting functionality, and provides the plug device with increased originality and practicability.