Wetland is one of the largest carbon sink among all terrestrial ecosystems,and regarded as the main emission source of methane (CH_4) in the atmosphere.As CH_4 has 34 times warming potential of carbon dioxide (CO_2) per mole,it is of great importance to study the contribution of wetland as carbon sink or carbon source to global climate change.Totally,80% to 90% of CH_4 emissions come from microbial activity,and CH_4 flux in wetland is closely related to microbial composition,abundance and function of methanogens and methanotrophs.However,the studies on the effects and mechanisms of the functional microorganisms that control CH_4 cycling in wetland ecosystem is relatively decentralized.To better understand the microbial regulation mechanism of CH_4 emission process,we provide an overview of microbial community associated to CH_4 cycling,the factors influencing the microbial methane emission activity,and the microbial methane emission mechanisms in wetland ecosystem.Besides,we indicate further research needs on microbial-driven CH_4 emission and their potential response to climate change.