Negative pressure combustor capable of automatically adjusting air excess coefficient

A negative pressure combustor capable of automatically adjusting an air excess coefficient is mainly composed of a hearth, a PLC, a combustor body and an environment temperature detector. A pressure sensor is arranged in the heath, and an adjusting baffle is arranged in a chimney of the hearth; an air volume adjustor is arranged in an air inlet of the combustor body, and a flow meter and an air flow adjustor are arranged on a gas inlet pipe of the hearth; and an environment temperature detector, the adjusting baffle, the pressure sensor, the air volume adjustor, the flow meter and the air flow adjustor are connected with the PLC. According to the combustor, the air excess coefficient can be greatly reduced, forced ventilation of a negative pressure furnace is achieved, and therefore the combustion efficiency of the combustor is improved; the furnace efficiency of an existing negative pressure furnace can be improved, and even, use and popularization of the negative pressure furnace can be expanded; and becaus