The utility model relates to a bidirectional tightening device for a rubber cloth of a BB type printing machine, which comprises a rubber roller, a bite, a blanket, a teether, a tightening device composed of a cloth roller and a worm gear, characterized in that: one end of the blanket is characterized in It is connected by the tightening device on the blanket cylinder, and the other end is connected by another tightening device consisting of a cloth roller and a worm gear at the nip of the blanket cylinder. The utility model has the advantages that the rubber cloth can be fully tightened on the circumferential surface of the rubber roller, the width of the white side of the printing bite during printing is reduced, and paper is saved.