Due to climate change in recent years, extreme weather and corresponding natural disasters are frequently occurring, and people face severe challenges. Global environmental problem has attached a lot of attention. Wetland is one of the four terrestrial ecosystem. Although the world′s wetland only accounts for 4%-5% of the total land area, its carbon storage is up to 450Gt, equivalent to 20% of carbon in global terrestrial ecosystem. Wetland ecosystem doubles as carbon sink and carbon resource. Carbon cycle has an important influence on global carbon budget and global climate change. Researching the exchange between wetland system and carbon of atmosphere contributes to thoroughly understand the effects that wetland ecological system act on environment of atmosphere. On the basis of biomass and determining green house gas emission, the exchange between four types of vegetation system of Baishazhou in Dongting Lake and carbon of atmosphere were studied. The results indicated: Poplar plantation、Phragmites and Carex these three types vegetation system its productivity respectively absorb carbon9.88、6.83 t·hm-2·a-1 and 4.07 t·hm-2·a-1 ，Carbon emitted by soil (including carbon of CH4)3.08、2.79 t·hm-2·a-1 and 2.80 t·hm-2·a-1，the three types vegetation system are sink which absorbs carbon 6.80、4.07 t·hm-2·a-1 and 1.27 t·hm-2·a-1every year. Mictium of Hydrilla and Potamogeton its net productivity absorb carbon 1.23 t·hm-2·a-1,soil discharge carbon 1.32 t·hm-2·a-1,the system is carbon source,which discharge carbon 0.09 t hm-2·a-1every year. If that CH4 green house effect is 21 times of CO2 convert into CO2,soil of Poplar forestry release CO2(including CH4converting into CO2)16.19 t hm-2·a-1,which is less 16.64 t·hm-2·a-1than net productivity of vegetation. This system is sink of green house for green house effect of atmosphere; Phragmites、Carex as well as mictium of Hydrilla and Potamogeton. Soil release CO2(including CH4converting into CO2)43.68、39.19and 32.22 t·hm-2·a-1,which is more 20.26 、24.27and27.71 t·hm-2·a-1 than vegetation net productivity absorbing.These three types wetland vegetation system are emission source of green house gas for green house effect of atmosphere, which reminds us that in the wetland study, we not only concentrate wetland soil organic carbon on accumulation of loss, but also care about CO2 which may be carbon sink of atmosphere or sources of emissions of atmospheric greenhouse effect.