The invention discloses a device used for paperboard cutting. The device comprises a driving gear, a first power unit, two conveying units and a driving mechanism. The axis of the driving gear is arranged in the vertical direction. The first power unit is used for driving the driving gear to rotate. The two conveying units are arranged on the two sides of the driving gear correspondingly. Each conveying unit comprises a bracket, a movable plate, a rack and a cutting knife. Each bracket is provided with a guide rail which is horizontally arranged. Each movable plate is movably installed on the corresponding guide rail. A plurality of containing grooves are formed in each movable plate in the length direction of the corresponding guide rail at intervals. The length direction of the containing grooves and the length direction of the guide rails are perpendicular or obliquely crossed. Each rack is installed on the side, close to the driving gear, of the corresponding movable plate. The racks are engaged with the driving gear. The first end of each cutting knife is rotationally connected with the corresponding bracket. The planes where the cutting knives are located are perpendicular to the length direction of the guide rails. The device used for paperboard cutting is simple in structure and good in machining effect.