The wetland behavior of mercury (Hg) ,which is related to human health closely, is an important part of Hg global cycle. In this paper, we expounded the significance of studying Hg behavior in wetland environment, and reviewed progress of study on wetland process of Hg over the world, including occurance, contents, speciation, frasportation, transformation, methylation and demethylation, interface exchanges of Hg. Because the wetland is unique in the aspect of hydrology course and environmental condition, the accumulation and transform characteristics of Hg is different from the other ecosystems. The wetland can absorb Hg of atmospheric deposition and runoff, so it is the sink of Hg. Hg presents the accumulation state in the wetland ecosystem. Wetland has high Hg accumulation rate and methylation capacity. In wetland, redox condition and abundant organic carbon are favorable to methylation of Hg. Wetland methylmercury threatens the human health through food chain's bioaccumulation. The global warming, acid rain and exhaustion of ozone layer may increase the risk of ecological environment of the wetland Hg. It is emphasized that we should research Hg cycle in special conditions of wetland, and should investigate the role of wetland in Hg global cycle, as well as should pay close attention to the response of Hg in wetland to global environmental changes.