The invention relates to a paper shredder with a heat dissipation function. The paper shredder comprises a main body, a fixed box and two paper shredding devices, and further comprises a heat dissipation mechanism and a paper shredding mechanism, wherein the heat dissipation mechanism comprises a water box, a water adding assembly, a connecting pipe, a rotating pipe, a rotating assembly, two first bearings and two control assemblies, and the paper shredding mechanism comprises a transmission assembly, a connecting assembly and two paper shredding assemblies. According to the paper shredder with the heat dissipation function, through the heat dissipation mechanism, the functions of cooling and heat dissipation of a rotating box and a cutting edge are achieved, the situation that due to the fact that the temperature of the cutting edge and the rotating box is too high, paper fire breaks out is avoided, and therefore the normal work of paper shredding is prevented from being affected, and the paper shredding devices is prevented from being damaged, the safety of the paper shredder is improved, the paper shredding mechanism is used for achieving a secondary shredding function of paper, the paper is completely shredded, the paper cannot be spliced together again, information on the paper is prevented from being leaked, and the safety is improved.