Global-warming is one of the important environmental problems.Previous studies often interpreted the influence of land-use change to climate by studying the change of the earth surface's parameters.But the increase of greenhouse-gases

an important factor which influence the climate is neglected.By analyzing the data of fluxes of greenhouse-gases from various land-use types in Sanjiang plain

we compare the influence of different landuse to climate.The result expresses that the greenhouse effect of woodland>Calamagrostis angustifolia>Carex lasiocarpa>Carex pseudo-curaica>paddyfield>soybean are different.The magnitude of the influence can be soybean>Calamagrostis angustifolia>Carex lasiocarpa>woodland>paddyfield>Carex pseudo-curaica.So

if the wetlands will be changed into farm land

the rice paddy is more suitable than dry land.In the past years

for the land-use change in Sanjiang plain

total quantity of different greenhouse-gases has changed.Among them

the amount of CH_4 decreased

but that of CO_2

N_2O increased.The increase of GWP which is resulted by land-use change is one of important factors of region climate warming.