In recent years, northern Tibet has experienced significant warming and precipitation rises. Greenhouse gases(GHGs)are not only the main cause of climate change, but they also have an important feedback effect on climate. In this study, we conducted an in situ irrigation experiment in an alpine meadow(4500 m above the sea level)to simulate the effects of future rainfall increases on GHG emissions and biomass in northern Tibet. Three treatments:control(CK), low water(DS), and high water(GS)were set up. A static chamber and gas chromatography method were used to measure the GHG emissions. Results showed that a increase in soil moisture led to significant increases in grassland biomass, carbon dioxide(CO_2)emission, and nitrous dioxide(N_2O)emission, but decrease in methane(CH_4)uptake. A linear positive correlation between CO_2/CH_4 emissions and soil moisture was found(P<0.05). Nitrous oxide emissions had a significant quadratic relationship with soil moisture(P<0.05). However, there was no correlation between CO_2/CH_4/N_2O emissions and soil temperature. Taken together, significantly increased GHG emissions will have a positive feedback effect on climate change in the alpine meadows of northern Tibet under future precipitation scenarios. A further research on the interaction between GHG fluxes and plant photosynthesis, soil carbon, and soil nitrogen is necessary to determine the contribution of alpine meadows to climate change.