NOVELTY - Purifying methane, comprises: (a) selecting a booster fan to increase methane pressure; (b) filtering the obtained methane; (c) selecting a desulfurizing bacteria; (d) heating the methane, entering a preheated mixture in a reactor, and cooling the mixture; (e) pressurizing methane; (f) entering the pressurized methane into a packed tower, performing an air drying process on the methane, evaporating the barren solution, recovering methane, desorbing, filtering and cooling the solution; and (g) reducing methane dew point, and filling two fixed beds with sieve or aluminum oxide.    USE - The method is useful for purifying methane, which is useful as vehicle fuel gas or infusing gas.    ADVANTAGE - The method allows easy and economical purification of the methane in an environmentally-friendly manner.    DETAILED DESCRIPTION - Purifying methane, comprises: (a) selecting a booster fan to increase methane pressure to 1.02-1.55 atmosphere; (b) filtering to remove dust impurities using a filter screen, where the filter screen has an aperture of 0.01-2 mm; (c) selecting a biological desulfurizing bacteria as desulfurizing agent to translate hydrogen sulfide into simple substance sulfur, reducing concentration of the hydrogen sulfide in the methane to be less than 300 ppm; (d) heating the methane at a temperature of 150-400 degrees C in a preheater after removal of the hydrogen sulfide, entering the preheated mixture in a fixed bed reactor filled with a deoxidizing catalyst, reacting oxygen with methane gas, reducing volumetric concentration of the mixture to be less than 0.5%, entering the mixture into a cooler, and cooling the mixture at a temperature of 30-80 degrees C; (e) pressurizing methane to 0.5-3 MPa; (f) entering the pressurized methane into a packed tower containing water, propylene carbonate, an activated methylenedioxyethyaamphetamine and other organic amine absorbents as absorbents of an absorption system with absorption pressure of 0.5-3 MPa and absorption temperature of 10-60 degrees C, performing an air drying process on the purified methane, flash evaporating the barren solution under pressure of 0.3-0.8 MPa, and recovering methane, desorbing the solution after flash evaporating at desorbing temperature of 10-130 degrees C under desorbing pressure of 0.1-0.15 MPa, maintaining an outlet pressure of the desorbing fan to be 1.02-1.5 atmosphere, where outlet flow of the desorbing fan is 1.5-25 times of volume flow of absorbent, and filtering and cooling barren solution; and (g) reducing methane dew point to be lower than 5 degrees C in an air dryer, alternately filling two fixed beds with molecular sieve or aluminum oxide, where one of the filled beds is used for absorption purpose and the other bed is used for regenerating purpose, reducing the methane dew point to be lower than -15 degrees C, absorbing hydrogen sulfide and carbon dioxide, and decompressing into a bottle. An INDEPENDENT CLAIM is included for a device for purifying methane, comprising a fan (1) for transporting methane, a first filter (2), a biological desulfurizing tank (3), a first compressor (5) for increasing pressure in flow pass, a buffer tank, a packed tower for absorbing carbon dioxide and hydrogen sulfide, an air dryer, a fixed bed dewatering device, a second compressor for compressing purified methane and a purified gas storage tank, where: the biological desulfurizing tank comprises a tank reactor for dispersing the desulfurizing bacteria in water, making methane to enter from the bottom of the agitated reactor, passing a distributor and processing a gas-liquid contact reaction in a form of bubbles; a deoxidizing device is placed between the biological desulfurizing tank and the first compressor and provided with a heater for heating methane, a fixed bed reactor (4) for reacting oxygen with methane gas and a cooler for cooling methane; and the deoxidizing catalyst is used in the fixed bed reactor.