The invention discloses a waste paper recycling device for a paper mill. The waste paper recycling device comprises a protection shell, a partition is welded in the middle of the inner wall of the protection shell, an opening is formed in the middle of the partition, a paper inlet is formed in the middle of the top of the protection shell, a hand protection retaining plate is connected on one sideof the top of the paper inlet through bolts, a guide retaining plate is connected at the top of the other side of the paper inlet through bolts, the bottom of each of the hand protection retaining plate and the guide retaining plate extends to the inside of the protection shell, a roller support is connected in the middle of the inner wall top of the protection shell through bolts and positionedat the bottom of the hand protection retaining plate, and a paper guide roller is connected at the bottom of the roller support through a bearing. The waste paper recycling device improves paper recycling and treating efficiency, and obtained paper pulp is high in quality of fiber and washes away paper pieces adsorbed inside the device; drainage traces can make water flow to form eddy, so that impact force is enhanced, and the problem that a paper shredding device gets stuck is solved.