[Objective] This study is to analyze the carbon source and sink variation of agriculture ecosystem and its driving factors in Iri Valley in order to provide the scientific basis for agricultural structure adjustment and agricultural production of carbon emissions.[Methods] Based on the statistical data of crop yield, planting area, agriculture inputs in the period from 2004 to 2013, the carbon coefficient, the amounts of carbon source and sink of agriculture ecosystem in Iri Valley were calculated.[Results] (1) The total carbon absorption was increased from 2.32×10⁶ t in 2004 to 4.48×10⁶ t in 2013 with a rate of 7.57% each year. Carbon absorption per unit of sowing area was increased from 7.54 t/hm² in 2004 to 9.27 t/hm² in 2013 with the times of 0.23. The correlation analysis results showed that carbon absorption had significantly positive correlations with the yields of rice, wheat, corn and vegetables, while significantly negative correlation with the yield of linseed. (2) The total carbon emission was increased from 2.24×10⁵ t in 2004 to 4.02×10⁵ t in 2013, which increased by 0.80 times during the past 10 years. Diesel and fertilizer inputs were the most important factors that influenced carbon emission. (3) The net carbon absorption was increased from 2.10×10⁶ t in 2004 to 4.07×10⁶ t in 2013, and net carbon absorption per unit of sowing area was increased from 6.81 t/hm² in 2004 to 8.44 t/hm² in 2013 with a increasing rate of 2.41% each year.[Conclusion] With the high input and output model, the agriculture ecosystem in Iri Valley showed as a carbon sink.