The invention discloses a medical waste disposal device which comprises a disinfection tank. A liquid inlet pipeline is arranged at the top of the disinfection tank. A liquid storage cavity is formed in the disinfection tank. A first filter screen is arranged at the top of the liquid storage cavity. A water pump is arranged in the liquid storage cavity. A water pipe is fixedly connected to the bottom of the water pump. Shower nozzles, which are arranged in an equally-spaced manner, are arranged on the water pipe. A feeding pipeline is arranged on one side of the disinfection tank. A filter plate is arranged at the bottom of the liquid storage cavity. A waste water storage cavity is formed in the bottom of the filter plate. The medical waste disposal device has the advantages that medical waste in the disinfection tank can be effectively disinfected, a solid-liquid separation effect on the medical waste is achieved, the medical waste in a grinding box can be effectively ground, incineration disposal of the medical waste is facilitated, and the medical waste can be effectively incinerated more thoroughly.