The utility model discloses a furnace bottom roller cleaning device for a medium and heavy plate heat treatment furnace. The device aims to solve the problem that an existing furnace bottom roller cleaning device is poor in cleaning effect, and comprises a steel plate. Hooks are installed on the upper surface of the steel plate, the lower surface of the steel plate is provided with a plurality of parallel grooves at intervals, the lower surface of a protruding block between every two adjacent grooves is a concave arc face matched with the outer circumferential arc face of a furnace bottom roller, and the two sides of the bottom of each groove are fillets. The lower surfaces of the cleaning device is a concave arc face and is completely matched with the roller surface of the furnace bottom roller, so that contact area is effectively increased, and secondary damage to the roller surface is avoided in the cleaning process while the cleaning effect is guaranteed; large shearing force is formed due to movement of the steel plate and the furnace bottom roller in opposite directions, the cleaning effect is improved, the device can be repeatedly used even if a small part of the lower protruding blocks are damaged, and the furnace bottom roller can not be damaged; the two sides of the bottom of each groove are the fillets, so that oxide scale and nodules scrapped into the grooves are convenient to clear away thoroughly, large containing space is provided, and work efficiency is improved.