The invention discloses a medical waste treatment device with a disinfection function. The device comprises a casing, a feed hopper, a liquid box, crushing rollers, a sieve plate, a support plate anda collecting cavity, wherein the feed hopper is arranged in the middle of the upper end of the casing, and the support plate is fixedly mounted at the lower end of the inner side of the casing; a cavity is formed in the inner side of the support plate, a first baffle is glidingly connected in the cavity, a second spring is connected with the left end of the first baffle, a slider is fixedly connected with the right end of the first baffle, and a second baffle is glidingly connected with the right end of a discharging hole. The device is novel in design, when the sieve plate rotates upwards, waste on the sieve plate falls out under the action of gravity, a waste liquid and a disinfectant for disinfection fall out of the sieve plate, solid-liquid separation treatment is realized, meanwhile,the disinfectant at the upper end of the support plate is mixed with solid waste when through holes in the first baffle and the support plate are staggered, the treatment time of the disinfectant is prolonged, and the disinfection effect is improved.