The invention discloses a preparation method of a municipal sludge concrete floor tile, which comprises the following steps of uniformly mixing urea, formaldehyde and water, regulating the pH value ofa system to be 9 to 9.6, raising the temperature and stirring, adding lecithin, halloysite nanotube and N,N-dimethylformamide and uniformly stirring, adding polystyrene and stirring, performing vacuum hot-pressing sintering to obtain a prefabricated material; uniformly mixing municipal sludge and the prefabricated material, aging and standing, then adding corncob powder, slag, talcum powder, calcined kaolin, volcanics and shell carbon and stirring, piling and aging to obtain a floor tile green body; drying the floor tile green body in shade, performing forced air drying, then sintering, cooling to obtain the municipal sludge concrete floor tile. The preparation method provided by the invention is simple and is easy to operate; in addition, the obtained concrete floor tile is light in weight, high in strength, good in water resistance, and is not easy to deform, is safe and pollution-free, environmentally friendly and energy-saving, and the random emission of municipal sludge is reduced.