The invention relates to the field of paper shredders and discloses an automatic paper shredder suitable for combined work and an automatic paper shredding method. The paper shredder comprises a master controller, a plurality of waste paper containing boxes (1), a plurality of automatic paper shredding units (30) and at least one man-machine interaction device (21), wherein the waste paper containing boxes (1) are connected to the automatic paper shredding units (30) in an one-to-one correspondence manner; each of the automatic paper shredding units (30) comprises an automatic paper feeding channel and a paper shredder (9), and the paper shredder (9) is matched with and connected to each of the waste paper containing boxes (1) through the automatic paper feeding channel; the man-machine interaction device (21) provides a user with a human-machine interaction interface, and the master controller is electrically connected to the paper shredders (9) for receiving control signals sent by the man-machine interaction device (21) to control the working states of the corresponding paper shredders (9). The paper shredder provided by the invention has multiple groups of waste paper containing boxes and automatic paper shredding units, can be used by many people at the same time, and can realize the paper shredding function in an unattended operation, so that the office efficiency of the user is improved.