Farmland ecosystem carbon sequestration includes two parts:crop biomass and farmland soil carbon sequestration. China's farmland ecosystem has a large area and high carbon storage, and is an important part of the global ecosystem carbon cycle. It is of great significance to clarify the content, change rate and the influencing factors of crop biomass and soil organic carbon in China for deepening the scientific understanding of global ecosystem carbon sink and maintaining food security. In this review, the related concepts of farmland ecosystems carbon were analyzed firstly, and the associated methods on carbon sinks were compared. Based on previous studies and SoilGrids250 data, the spatiotemporal distribution of carbon pools in farmland ecosystems in China was analyzed, and the influencing factors and carbon sequestration methods of farmland ecosystems were also analyzed. The results showed that the crop biomass in China has been increasing in the past 30 years, and farmland soil organic carbon content was low and its spatial distribution was uneven. Fertilizer and organic residue management, conservation tillage, planting patterns, irrigation and other management measures were the main measures to increase soil organic carbon sinks, but there were still uncertainties in the estimation of the carbon sink potential of farmland ecosystems. Finally, future research directions were put forward from three aspects:improving estimation accuracy of farmland ecosystem carbon sequestration, studying the influencing mechanism of both climate change and human activities, and developing agricultural technology to promote carbon sequestration. This review results help to promote scientific research and technology promotion of carbon sequestration in farmland ecosystems, and seek pathway for realizing "carbon neutrality" of farmland ecosystems.