Research on soil erosion during the construction of newly added cultivated land in mountainous areas can not only ensure the stability of newly added land, but also play an extremely important role in achieving environmental friendliness. After planting soybeans, the SOC content was lower than that of corn planting. Among them, the SOC of the 2° test field was reduced by 13.81%, the 3° test field was reduced by 16.69%, and the 5° test field was reduced by 2.94%. Compared with corn planting, the TN content of the soybean test field was reduced, among which the 2° test field decreased by 3.51%, the 3° test field decreased by 14.86%, and the 5° test field decreased by 4.69%. The cumulative effect of carbon and nitrogen content in the 3° experimental field under the corn planting mode was better.