The present invention relates to an ESD protective device, wherein, the device is a multi-finger MOS protective device, comprising: a plurality of enhanced MOS tubes arranged in matrix. Source electrodes and grid electrodes of the MOS tubes are grounded; the base
electrode of the parasitic
triode of each MOS tube is grounded through a base
electrode resistor; a multi-finger-
type metal layer is formed like that the drain
electrode of the MOS
pipe of each column is covered by the
metal layer which is overlapped with two columns of grid electrodes adjacent to the drain electrode, and the
metal layer is not only connected with a PAD but also connected with the drain electrode; the
parasitic capacitance is produced as the
metal layer is overlapped with the grid electrode. For the ESD protective device of the invention, when ESD pulse appears, the
parasitic capacitance couples the
grid voltage to a nonzero potential so as to produce enough leakage current, so that parasitic triodes of the ESD protective device are simultaneously conducted and discharged. Thus, the conducted
voltage is reduced. Besides, the uniformity of conduction is high and ESD protected capability is highly improved.