Abstract: 【Objective】 To study the change characteristics of soil organic carbon content and its influencing factors of cultivated land in northern Xinjiang in the past 40 years. 【Method】 Representative data were obtained by collecting data from the second soil survey in Xinjiang in 1980 and soil series survey data in 2014, such as variance analysis, correlation analysis, and regression analysis to combine total soil nitrogen, total phosphorus, pH, and climate with influencing factors such as the amount of agricultural chemical fertilizers, the overall trend and vertical change characteristics of the organic carbon content of different soil types in the two periods were compared and analyzed, and the natural and man-made driving factors affecting this change were discussed. 【Result】 (1) In 2014, the average organic carbon content of different cultivated land soil types in northern Xinjiang increased by 1.61 g/kg compared with 1980, with a change rate of 4.73%. Among them, gray desert soil and brown calcium soil had the most significant increase, with a change rate of 20.27% and 15.75%. On the contrary, the organic carbon content of swamp soil lost significantly (27.74 g/kg), and the change rate reached 81.58%. (2) According to the vertical distribution of soil organic carbon content of 0-100 cm soil in northern Xinjiang arable land during the two periods, the organic carbon content of most soil types showed a trend of decreasing with the depth of the soil layer; comparison of different soil types in the same soil layer, 2014 organic carbon content of chernozem soil, chestnut soil, meadow soil, and marsh soil surface (0-20 cm) of cultivated land was lower than the average organic carbon content in 1980, and the decline was 24.57%, 6.76%, 18.15% and 121.174%. In 2014, the average organic carbon content of brown calcium soil and gray desert soil increased compared with the 1980 average by 15.95% and 16.12%. (3) There was a significant positive correlation between soil organic carbon and total nitrogen in 1980 and 2014. The correlation coefficients were R²=0.722,1 and R²=0.116,1 respectively, which were positively correlated with total phosphorus, but slightly correlated with pH. (4) In the past 40 years, the soil organic carbon content in northern Xinjiang was on the rise. Discussing the main factors influencing the change of organic carbon content, it was concluded that it is mainly affected by soil type, climatic factors, soil physical and chemical properties, fertilizer application and human activities. 【Conclusion】 In the past 40 years, the soil organic carbon content of cultivated land in northern Xinjiang has generally increased, and the soil organic carbon content of different soil types is quite different. The soil organic carbon and total nitrogen are significantly correlated, which is affected by many factors.