1. A DC relay having a function of extinguishing arc and resisting short-circuit current, comprising two stationary contact leading-out terminals, a straight sheet type movable spring, a push rod component and four permanent magnets, the movable spring is mounted on the push rod component, so that the movable contacts on the two ends of the movable spring are matched with the stationary contacts on bottom ends of the two stationary contact leading-out terminals under the action of the push rod component, wherein the four permanent magnets are respectively arranged on two sides in the width direction of the movable spring corresponding to the movable and stationary contacts, magnetic poles on sides facing to the movable and stationary contacts of the two permanent magnets corresponding to the same pair of the movable and stationary contacts are opposite, and the magnetic poles on a side facing to the corresponding movable and stationary contacts of two permanent magnets on the same side in the width of the movable springs are set to be the same; and a yoke clip is connected between the two permanent magnets corresponding to the same pair of the movable and stationary contacts, upper magnetizers arranged in a width direction of the movable spring are mounted above the position between the movable contacts of the movable spring, lower magnetizers arranged in the width direction of the movable spring and of moving with the movable spring are mounted below the position; at least one through hole is provided in the movable spring at the position, so that the upper magnetizers and the lower magnetizers can approach one to another or come into contact with each other through the through holes, at least two independent magnetically conductive loops are formed in the width direction of the movable spring by the upper magnetizers and the lower magnetizers, increased magnetic pole faces of the respective magnetically conductive loops at the corresponding through holes are used such that when the movable spring has a large fault current, attraction force in a contact pressure direction is generated to resist an electro-dynamic repulsion force generated, due to the fault current between the movable spring and the stationary contact leading-out terminals.