The invention provides a combined garbage incinerator, belongs to the technical field of garbage incineration equipment, and solves the problem that a conventional garbage incinerator is easily forcedto be shut down due to a blockage in or other failures of a flue gas treatment system positioned above the conventional garbage incinerator. The combined garbage incinerator is characterized in thata heat medium outlet of a waste heat boiler communicates with the flue gas treatment system through a second pipeline; the flue gas treatment system comprises a bag-type dust remover and a flue gas washing tower; the cross section of the flue gas washing tower takes a three-petal shape; a porous partition plate is arranged between every two adjacent petals; a flue gas treatment chamber is formed between every two adjacent porous partition plates and the flue gas washing tower; a water solution inlet is formed in the side wall of the upper part of the flue gas washing tower; a water supply tubeis inserted into the water solution inlet; three nozzles are arranged on the water supply tube in a communicating manner and correspondingly positioned in the three flue gas treatment chambers; a flue gas inlet is formed in the bottom of each flue gas treatment chamber; and the bag-type dust remover communicates with the three flue gas inlets through a third pipeline.