Purpose <p>Applying mariculture sludge (MS) to paddy fields has substantial implications for environmental sustainability and food security. A comprehensive analysis of the chemical properties, enzyme activity, and bacterial community structure in paddy soils under MS combination offer valuable insights for optimizing paddy field management practices.</p> Methods <p>MS, Acidic and alkaline rice-field soil samples were collected. Three combinations were prepared: MS with acidic paddy soil (SA), MS with alkaline paddy soil (SL), and acidic and alkaline paddy soil (AL). To investigate adaptive changes in soil properties and bacterial communities on days 32 and 64.</p> Results <p>Our findings revealed MS exhibited higher nutrient content and enzyme activities than paddy soil, leading to an increased concentration of available nutrients in the pore water of paddy soil and enhanced activity of carbon-acquiring enzymes. After 64 days, the MS combination improved the soil quality index by 147.54% in acidic paddy soils and by 15.28% in alkaline paddy soils. This improvement was directly influenced by the soil bacterial community and enzyme activity, with pH and total organic carbon playing indirect roles. Furthermore, MS induced a stochastic shift in bacterial dynamics within paddy soil, increasing the stability of the co-occurrence networks. Notably, MS facilitated the emergence of keystone species and biomarkers involved in carbon cycling. The FAPROTAX analysis revealed that MS promotes the breakdown of organic matter in paddy soils, supporting vital ecological and environmental functions.</p> Conclusions <p>These insights highlight MS effectiveness in regulating paddy soil bacterial community compositions, enhance the quality of soils, increase the relative abundance of beneficial bacteria, and optimizing carbon cycling mechanisms within paddy environments.</p>