Microbially enhanced coalbed methane (MECoM), which can produce new coalbed methane (CBM) and efficiently release the stress of energy needs, is the hot point in the study on the exploitation and enhancement of CBM. The mechanism of MECoM is the production of methane via anaerobic biodegradation of coal. Stimulation experiments have been performed to investigate the ability of indigenous and exogenous microorganisms to produce methane by degrading coal. And the influential factors have been analyzed in laboratory as well. Diverse methanogenic flora have been obtained through enrichment or isolation methods by some CBM companies. The methods of field implementation have also been investigated. The abilities of microorganisms to produce methane by coal biodegradation could be improved by developing new methods of coal pretreatment, and structuring new microbial flora with high potential to degrade coal, which would promote the application of MECoM.