As global changes intensify,terrestrial ecosystems carbon cycle has attracted much attention.In recent years,influences of precipitation pattern change and nitrogen deposition increase on the ecosystems carbon cycle are deeply studied.We reviewed the effects of precipitation pattern change and nitrogen deposition increase on grassland ecosystem carbon cycle and its internal mechanism under global climate change.Changes in precipitation amount,timing and frequency,or nitrogen deposition amount,frequency and form could alter the composition and structure of community by the ways of changing soil water content, soil temperature,soil nutrient and the soil microbial activity,and then influence the ecosystem carbon cycle finally.However,whether interactive effects between precipitation pattern and nitrogen disposition exist in different regions have no uniform conclusion yet.Therefore,more studies are needed to explore the response mechanisms of ecosystem carbon cycle to precipitation and nitrogen deposition under global climate change.