The invention discloses a method for treating incineration tail gas of solid hazardous waste, comprising the following steps of: (1) taking manganese dioxide as the oxidant, adding water to prepare a sizing agent; (2) delivering the size into the smoke absorption tower, spraying the sizing agent in mist, wherein the pressurized smoke with the wind pressure of 1500-5000pa is introduced from the bottom of the tower, the gas inlet tubes are dispersed tubes under the liquid level of the recovery liquid at the tower bottom, wherein the temperature T of the tower bottom recovery liquid is controlled to be not below 5 DEGC and not above 90 DEG C, and the pH value is not less than 3.8; (3) separating the precipitation from the recovery liquid at the tower bottom, preparing manganese sulfate via the solution, and recovering the heavy metal from the bottom dross; (4) discharging the tail gas which is up to the standard. The method for treating incineration tail gas of solid hazardous waste has simple process flow, non-fouling equipment, smooth circulation, less equipment, and low operation cost; and the composite rate of removing the harmful substances reaches 98.5%. The heavy metals can be recovered from the bottom dross; the recycle and the harmlessness can be realized without secondary pollutant products.