The system is for Press machine. It employs hydraulic pressure for activating the platen to knock out. It is totaly different from the conventional mechanical structure, and can prevent the board and the dies from being heavily impacted by the press, thus minimize the breaking of pierce pin and prolong the dies service life. 1） This system employs hydraulic pressure for activating the plate to knock out. It can prevent the board and the dies from being heavily impacted and minimize the breaking of pierce pin. 2） Holder function is provided in order to avoid cracking, flaking and burr during hole piercing.