Inner hexagonal fastener capable of measuring pressing force

The inner hexagonal fastener capable of measuring the pressing force comprises a nut and a screw rod arranged below the nut, two contact via holes penetrating through the nut are formed in the bottom of an inner hexagonal structure of the nut, lower openings of the contact via holes are located outside the outer diameter of the screw rod, a plurality of upward insertion holes are formed in the bottom face of the nut, and the insertion holes are communicated with the nut. An anti-rotation protection piece is inserted into the insertion hole, the anti-rotation protection piece is provided with a plurality of insertion protrusions matched with the insertion hole, the anti-rotation protection piece is provided with a through hole allowing the screw to pass through, a pressure induction piece is arranged between the anti-rotation protection piece and the bottom face of the nut, and the pressure induction piece transmits a pressure signal to a processing unit through a contact via hole by means of a signal line; ac