NOVELTY - A combined natural gas purification plant and low concentration acid gas processing apparatus comprises a solid phase oxidation reaction device and a liquid phase oxidation reaction device, which ere connected in series. The solid phase oxidation reaction device comprises an isothermal reactor, which is connected to acid gas separator, the acid gas separator and the isothermal reactor are connected via acid gas booster fans and acid gas pre-heater. The liquid phase oxidation reaction device comprises absorption oxidation tower, which is connected to a gas-liquid separator.    USE - Combined natural gas purification plant and low concentration acid gas processing apparatus (claimed).    ADVANTAGE - The apparatus provides high quality of sulfur with high sulfur recovery rate of more than 99.9% and low capacity acid gas, hence reducing the operation cost.    DETAILED DESCRIPTION - A combined natural gas purification plant and low concentration acid gas processing apparatus comprises a solid phase oxidation reaction device and a liquid phase oxidation reaction device, which ere connected in series. The solid phase oxidation reaction device comprises an isothermal reactor, the upper end inlet of the isothermal reactor is connected through a pipeline to acid gas separator, the entrance terminal of the acid gas separator is connected to an acid gas pipeline, the acid gas separator and the isothermal reactor are connected via acid gas booster fans and acid gas pre-heater, the isothermal reactor upper end is connected in series to an air inlet pre-heater and an air blower, the air blower is connected the upper part of an air inlet pipeline, and the isothermal reactor in the lower end has an outlet to a first-stage sulfur condenser, whose outlet is connected a sulfur condensing separator. The liquid phase oxidation reaction device comprises absorption oxidation tower, which is connected to a gas-liquid separator in the entrance end, the gas liquid separator has a tail gas condenser, and the sulfur condensing separator of the solid phase oxidation reaction device and the tail gas condenser outlet of liquid phase oxidation reaction device are connected. There is a heat insulating reactor, a sulfur condenser and a sulfur condensation separator connected between the first-stage sulfur condensation separator and a tail gas condenser. The upper end entrance of the isothermal reactor has a gas bag, whose bottom outlet is connected to isothermal reactor and lower end outlet is connected to a boiler water supplement pipeline. The absorption oxidation tower is set with a filter and an air blower. The absorption oxidation tower is cone-shaped, and has a pump at the bottom. The liquid phase oxidation reaction device comprises a heat exchanger, whose two ends are connected to the absorbable oxidation tower. An INDEPENDENT CLAIM is included for natural gas purification and low concentration acid gas processing method.