The invention relates to a screw. The screw comprises a screw head and a screw rod. The screw is characterized in that a cross groove is formed in the screw head and comprises a transverse groove bodyand a vertical groove body vertically crossed and connected with the transverse groove body; the left outer side wall of the upper end of the vertical groove body and the upper outer side wall of theleft end of the transverse groove body are connected through a first reinforcing rib; the right outer side wall of the upper end of the vertical groove body and the upper outer side wall of the rightend of the transverse groove body are connected through a second reinforcing rib; the right outer side wall of the lower end of the vertical groove body and the lower outer side wall of the right endof the transverse groove body are connected through a third reinforcing rib; and the left outer side wall of the upper end of the vertical groove body and the lower outer side wall of the right end of the transverse groove body are connected through a fourth reinforcing rib. The screw has the beneficial effects that the groove bodies can be better protected and are not prone to being damaged under the function of the reinforcing ribs, and the screw head can be mounted through a wrench as the screw head is a hexagonal screw head.