By analyzing and predicting the changes in soil organic carbon content of maize fields in Qianqiaozi Village，Huairou District，we reveal the key influencing factors affecting organic carbon changes and provide a scientific basis for achieving carbon sequestration and emission reduction targets in Beijing，China. In this study，the DNDC model was validated using the actual measured organic carbon data from 2016 to 2019 in the maize fields，and then the main influencing factors such as climate，soil and material return were selected to conduct sensitivity analysis on the validated DNDC model，and finally the future （to 2100） organic carbon changes under different typical concentration pathways （RCP8.5，RCP4.5） were simulated. The results showed that： the calibrated DNDC model can simulate the soil organic carbon changes in this maize field well； the initial organic carbon content and straw return rate are the main influencing factors of organic carbon changes； the organic carbon content increases significantly under RCP8.5 and RCP4.5，and the soil carbon pool reaches equilibrium at about 77 years，and the organic carbon content reaches 27.70 g/kg and 29.03 g/kg by 2100，respectively. The DNDC model can be used to study organic carbon changes in maize fields in this study area，and this management approach can be used to sustain carbon sequestration in the future.