Provided is a waste water incineration method including (S10) supplying waste water to an evaporator to evaporate the waste water, (S20) supplying an evaporator top discharge stream discharged from the evaporator to an incinerator to incinerate the discharge stream, (S30) mixing a first incinerator discharge stream and a second incinerator discharge stream discharged from the incinerator to form a mixed discharge stream, and (S40) heat-exchanging the mixed discharge stream and a fresh air stream in a first heat exchanger, wherein the mixed discharge stream which has passed through the first heat exchanger is heat-exchanged in a second heat exchanger and discharged to the atmosphere.