The utility model provides a special combustor for a dimethyl ether gas water heater. The special combustor comprises a base, an ejector and a plurality of combustion fire rows, wherein the inner part of the base is provided with a gas mixing chamber, and one side of the base is provided with a gas inlet communicated with the gas mixing chamber; the ejector takes strip shape and is fixedly installed on the base; the inner part of the ejector is provided with an ejection passage along length direction; the ejection passage is communicated with the gas mixing chamber; at least one side wall of the ejector is provided with an ejection nozzle communicated with the ejection passage; the plurality of combustion fire rows take the shape of long sheets and arranged and fixed on the base at intervals; each combustion fire row is provided with at least one combustion passage that is communicated with the ejection nozzle; and the combustion fire rows are also provided with a plurality of combustion holes communicated with the combustion passage. The special combustor allows the full combustion of dimethyl ether gas and can conveniently regulate the fire amount.