The invention discloses methane purifying comprehensive utilization technology, which is performed by the following steps: firstly, collecting generated methane, and washing the methane with water to remove solid impurities therein; secondly, performing alkali cleaning with aqueous solution of calcium hydroxide to neutralize and remove acidic materials such as sulfureted hydrogen, carbon dioxide and the like in the methane, and discharging the neutralized waste liquor through a drain pipe; and finally, drying the methane with a dryer, and discharging the methane into a storage tank with a compressor for later use. The technology is characterized in that: the drain pipe is connected to a carbonization tower, so the waste liquor flows into the carbonization tower; sufficient carbon dioxide gas is introduced into the waste liquor in the carbonization tower to ensure that surplus calcium hydroxide is subjected to reaction and is completely precipitated; the precipitated mixture slurry is pumped into a dehydration tank for dehydration, and the dehydrated and dried mixture is packaged into a chemical raw material; and the technology can fully reclaim the waste liquor substance of the alkali cleaning, further improves integral benefit, is easy to popularize and promote, and realizes circular benefit economy.