Abstract: In order to promote the sustainable development of cultivated land in black soil,the data of crop yield,soil organic carbon and total nitrogen were collected from the 38 years long-term fertilizer experiments in Heilongjiang Province.The effects of long-term fertilization on black soil organic carbon and total nitrogen content were verified and stimulated using the DayCent model,at the same time,the model optimization of correction factor was obtained by using the method of reverse simulation of test data,which analyzed the possible reasons for the deviation of the model simulation to reveal the influence of fertilization system on the dynamic change of soil carbon and nitrogen and the law of soil carbon and nitrogen transformation.The results showed that the root mean square error of SOC in CK,N,N2,NPK,M,MN and MNPK treatments were in range of 7.2%-9.8%,those of TN were in range of 7.1%-10.2%,which suggested that the simulated values were consistent with the observed values;but the root mean square error of SOC and TN in M2 and M2N2 treatment were in range of 13.2%,12.5% and 10.6%,10.4%,the evaluation parameters of the model simulation were in a good range,the DayCent model could basically reflect the changes of SOC and TN.The inverse modelling showed that SOC turnover rate of these（M,MN and MNPK）treatments was 1.7 times that of these（N,N2 and NPK）treatments.When applying a large amount of organic fertilizer in northeast China,soil nutrient balance,priming effects,the leaching and transferring issues of SOC should be considered in the DayCent model,which may overestimate SOC content to a certain extent.