【Objective】2,2-Bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), a typical persistent organic pollutant, remains widely accumulated in soil due to its high stability, posing severe threats to the ecological security of soil. Magnetite can enhance the efficiency of extracellular electron transfer of microorganisms, and dithionite, as a reducing agent, may drive the chemical reductive dechlorination of DDT. Thus, this study aims to elucidate the effect and its mechanism of the interaction of nano-magnetite (Fe3O4) and Na2S2O4 on the anaerobic degradation of DDT in paddy soil. 【Method】A slurry anaerobic incubation experiment using hydragric Acrisols was designed by setting up the following eight treatments: (1) Unsterilized DDT-contaminated soil (CK), (2) Unsterilized DDT-contaminated soil+nano-Fe3O4 (Fe3O4), (3) Unsterilized DDT-contaminated soil+Na2S2O4 (Na2S2O4), (4) Unsterilized DDT-contaminated soil+nano-Fe3O4+Na2S2O4 (Fe3O4+Na2S2O4), (5) Sterilized DDT-contaminated soil (S-CK), (6) Sterilized DDT-contaminated soil+nano-Fe3O4 (S-Fe3O4), (7) Sterilized DDT-contaminated soil+Na2S2O4 (S-Na2S2O4), (8) Sterilized DDT-contaminated soil+nano-Fe3O4+Na2S2O4 (S-Fe3O4+Na2S2O4). During the anaerobic incubation period, dynamic changes of pH, Eh, adsorbed Fe(II), and dissolved Fe(II) in slurries were regularly monitored, and their correlation with DDT degradation dynamics was quantitatively analyzed to reveal the driving factors of reductive dechlorination.?【Result】Results showed that the anaerobic degradation rates of DDT for different treatments were Fe3O4+Na2S2O4 > S-Fe3O4+Na2S2O4 > Na2S2O4 > S-Na2S2O4 > Fe3O4 > CK > S-Fe3O4 ≈ S-CK. After 42 d of anaerobic incubation, the extractable residues of DDT decreased by 77.0%, 68.4%, 66.2%, 60.8%, 56.1%, 52.6%, 30.2%, and 29.4%, respectively, for the treatments of Fe3O4+Na2S2O4, S-Fe3O4+Na2S2O4, Na2S2O4, S-Na2S2O4, Fe3O4, CK, S-Fe3O4, and S-CK. The dominant degradation product of DDT was 1, 1-dichloro-2, 2-bis(4-chlorophenyl)-ethane (DDD), with a small amount of 1, 1-dichloro-2, 2-bis(4-chlorophenyl)ethylene (DDE) and 1-chloro-2, 2-bis(4-chlorophenyl)ethylene (DDMU). Soil microorganisms, nano-Fe3O4, and Na2S2O4 all significantly enhanced the anaerobic degradation of DDT, and the order of their effects was Na2S2O4 > soil microorganisms > nano-Fe3O4, but there was no significant interaction among the three factors. A highly significant negative correlation was observed between DDT residues and the contents of adsorbed Fe(II) in the reaction systems, indicating that adsorbed Fe(II) was the key factor driving the anaerobic degradation of DDT. 【Conclusion】In conclusion, the combined application of nano-Fe3O4 and Na2S2O4 under flooded anaerobic conditions can effectively accelerate the reductive dechlorination of DDT in soil, which is a feasible remediation strategy for soils contaminated with polychlorinated organic compounds.