The invention belongs to the technical field of book making, and particularly relates to an automatic stacking machine for book making. The automatic stacking machine comprises a driving unit, a stacking unit and a bearing unit, and the driving unit is sequentially provided with the stacking unit and the bearing unit from top to bottom; the stacking unit comprises a fixing frame, an electric sliding block, a vertical plate, a pushing hydraulic cylinder, a pushing frame, a mounting plate, a rotating roller, a rotating motor, a conveying belt and a baffle. Books are stacked on the tray layer by layer through joint cooperation of the driving unit, the stacking unit and the bearing unit, and in the stacking process, the pushing mechanism and the conveying belt replace a mechanical arm to achieve the book stacking function, so that the time for switching the tightness state of the mechanical arm and adjusting the position of the mechanical arm is saved, and the working efficiency is improved. The stacking operation procedure is reduced, the requirement for the operation precision is relatively low, and the equipment investment cost and the later maintenance cost are reduced accordingly.