The invention relates to a novel surge protection device which mainly comprises a lightning protection element, a current sensor, an overcurrent protection device, a thermal protection device, a current limiter, a time-delay stepping electromagnet, an induction sheet, a separating contact, an arc-extinguishing gate, an arc-extinguishing magnetic blowout plate and upper and lower connecting terminals. The thermal protection device is arranged on the electrode of the lightning protection element. The lightning protection element is connected in series with the overcurrent protection device so as to form a surge discharge path. The current sensor sleeves the surge discharge path and is connected with the time-delay stepping electromagnet. The current sensor can sense current flowing through the lightning protection element and current is led into the time-delay stepping electromagnet. Power frequency current is introduced into the time-delay stepping electromagnet and then a series of mechanical linkage movement is actuated. The bypass circuit is conducted and the surge discharge path is shorted so that the protection effect of the surge protection device is realized.