Abstract: In this study, we aimed to analyze the effects of different straws on soil organic carbon (SOC), total nitrogen (TN), mineral nitrogen, and activated carbon and nitrogen including dissolve organic carbon (DOC), microbial biomass carbon (MBC), easily oxidized organic carbon (EOC), dissolve organic nitrogen (DON) and microbial biomass nitrogen (MBN). An incubation experiment lasting for 80 days under continuous flooding was conducted. Four treatments including exogenous addition of astragalussinicus straw (ZYY), exogenous addition of wheat straw (XM), exogenous addition of rape straw (YC) and no exogenous additions (CK) were set. The results indicate that the addition of straw (ZYY, XM, and YC) significantly increased the SOC content, and the largest increase range was observed in the YC treatment. The addition of straw had no significant effect on the TN. The mineral nitrogen content in the soil decreased significantly under the XM and YC treatment, and it was increased by 3.29% under the ZYY treatment. Additionally, the straw addition increased significantly the DOC content relative to the CK treatment. The DOC concentration in the XM and YC treatment were significantly higher than that in ZYY treatment. All treatments with straw addition significantly increased the MBC and MBN content relative to the CK treatment, and the content of MBC and MBN in ZYY and YC treatment were significantly higher than that of XM treatment. Compared with the CK treatment, the EOC content was significantly increased by 20.34% in the ZYY treatment, while it was increased by 9.36% and 10.53% in the XM and YC treatment, respectively, with no significant difference to the CK. The ZYY treatment significantly increased the DON content, while XM and YC treatment had no significant effect on the improvement of DON. In conclusion, the addition of straw especially rape straw can significantly improve soil SOC content. Astragalus sinicus straw had the best effect on soil active carbon and nitrogen, followed by rape straw and wheat straw.