The invention relates to a paper shredding method. The paper shredding method is based on a paper shredder. The paper shredder comprises a shell, a paper feeding assembly, a paper processing assembly,a discharging assembly, a power assembly and a controller; the paper feeding assembly comprises a storage box, a paper feeding table, a paper conveying roller and a paper feeding roller; the paper processing assembly comprises traction rollers and steel burr rollers; coloring nozzles, a drying assembly, a paper shredding sensor and paper shredding knife rollers are sequentially arranged below theburr rollers; a dust collector, an upper material liquid box assembly and a lower material liquid box assembly are arranged below the controller; the discharging assembly comprises a paper shreddingcavity equipped with an ultrasonic generator, a discharging screw rod and a discharging motor; a discharging sensor is arranged in the paper shredding cavity; the power assembly comprises a paper shredding motor; each roller shaft is connected with the paper shredding motor through a paper shredding synchronous belt; and the controller is connected with the above components through wires. The invention further discloses a working method of the paper shredder. According to the invention, early-stage anti-leakage treatment can be carried out before paper is shredded, the shredded paper reaches amicron grade, and leakage of information is prevented.