The invention relates to a garbage incinerator. The garbage incinerator comprises an incinerator grate, an incinerator throat part located above the incinerator grate, and a flue communicating with the incinerator throat part. The incinerator throat part is provided with a plurality of secondary air first nozzles. A plurality of secondary air second nozzles are arranged on the position, above the secondary air first nozzles, of the flue. The secondary air second nozzles and the secondary air first nozzles are both connected to a secondary air mother pipe. The garbage incinerator has the following advantages that 1, through transformation of an air distribution system, the burning capacity of original secondary air nozzles is shared, and thus coking of a hearth is delayed; and 2, the only space of a site is fully used, and the garbage incinerator is suitable for transformation of an aged unit.