The invention relates to a method for separating zinc from zinc-containing dust and sludge of an iron and steel plant, and belongs to the field of disposal of solid wastes. The method comprises usingammonium carbonate and ammonium bicarbonate to prepare a mixed solution, adding the mixed solution into the zinc-containing dust and sludge of the iron and steel plant, introducing compressed air to enable the reaction pressure to reach 0.12 MPa to 2.0 MPa, leaching for 60-240 minutes at the temperature of 30 DEG C to 120 DEG C, separating the solid and the liquid to obtain a zinc leaching liquidand a leaching residue comprising iron, carbon and calcium. The mixed solution comprising the ammonium carbonate and the ammonium bicarbonate is used as a leaching agent, the compressed air is introduced to main certain pressure, the zinc in the material is transformed into a soluble compound, the soluble compound enters the solution, but the elements of iron, carbon and calcium are not dissolved;meanwhile, the oxygen in the air is used as an oxidizing agent to accelerate the dissolution of the zinc under the pressurizing condition, so that the zinc is separated from the elements of iron, carbon and calcium in the zinc-containing dust and sludge of the iron and steel plant.