The invention discloses a combustor. The combustor comprises a bottom cup, a fire distributor and a fire cover; the bottom cup is provided with an air inlet passage, and comprises an upward inner ring nozzle and an outer ring nozzle which communicate with the air inlet passage; the bottom cup is provided with a reaching cavity communicating with the inner ring nozzle and the outer ring nozzle. The fire distributor is installed on the bottom cup, and comprises an inner ring venturi tube opposite to the inner ring nozzle and an outer ring venturi tube opposite to the outer ring nozzle; and the fire distributor and the bottom cup are alternately installed so as to form a gap. The fire distributor is provided with an inner ring mixing cavity communicating with the inner ring venturi tube and an outer ring mixing cavity communicating with the outer ring venturi tube and separated from the inner ring mixing cavity. The fire distributor is provided with an inner ring notch communicating with the inner ring cavity and an outer ring notch communicating with the outer ring cavity. The fire cover is installed on the fire distributor and covers the inner ring mixing cavity and the outer ring mixing cavity. So the inner ring flame and the outer ring flame formed by the inner ring mixing cavity and the outer ring mixing cavity cannot be interfered mutually.