<p> This study aims to investigate how different rice cropping systems influence topsoil organic carbon (SOC) accumulation, soil fertility, and bacterial community composition. Three representative rice cropping systems were selected: one-year regenerative rice (CZ), multi-year regenerative rice (DN), and single-season rice (DJ). Differences in topsoil organic carbon fractions, soil enzyme activities, and bacterial communities among these systems were systematically evaluated. The multi-year regenerative system exhibited the highest topsoil SOC content, with levels 40.1% and 60.3% higher than those observed in the single-season and one-year regenerative systems, respectively. Microbial biomass carbon (MBC) was greatest in the single-season system, approximately double that of both regenerative systems. Urease and acid phosphatase activities were significantly higher in the topsoil of multi-year regenerative and single-season systems than in the one-year regenerative system. Sucrase activity was particularly elevated in the single-season system, exceeding that of the other two by more than twofold. Additionally, the relative abundance of the nitrifying spirochete phylum was approximately 6.3% higher in the multi-year regenerative system than in the others. Overall, both the single-season and multi-year regenerative systems enhanced soil fertility and enzyme activity more effectively than the one-year regenerative system. Notably, the multi-year regenerative system showed the greatest potential for topsoil carbon sequestration. These findings highlight the ecological benefits of adopting multi-year regenerative rice systems, which offer a promising strategy for enhancing soil health and promoting the sustainable development of rice-based agroecosystems.</p>