Abstract: This study investigated the synergistic effects of straw returning combined with lime application on ameliorating acidic soil in South China, aiming to provide practical strategies for managing desilicated and allitic acid soils. A field experiment was conducted under double-cropping rice (early and late rice) systems with four treatments: (1) conventional fertilization (CF); (2) CF + quicklime (CFL); (3) CF + straw returning (CFS); (4) CF + straw returning + quicklime (CFSL). The results showed that CFSL and CFS treatments significantly increased early rice yields by 15.86% and 12.79%, respectively, compared to CF, while no significant differences were observed in late rice yields among treatments. In terms of soil acidification indicators, CFL and CFSL treatments significantly reduced exchangeable acidity and aluminum content, while increasing soil pH by 0.60 and 0.36 units, respectively. Additionally, CFS and CFSL treatments enhanced soil cation exchange capacity by 17.72% and 20.58%. Regarding soil organic carbon, CFSL treatment increased microbial biomass carbon and dissolved organic carbon by 26.53% and 34.20%, respectively, compared to CF. Soil enzyme activities, including urease, β-glucosidase, and sucrase, were also elevated by 33.60%, 12.25%, and 11.25%. Microbial community analysis revealed that CFSL treatment increased the relative abundance of Proteobacteria in bacteria, enhanced fungal alpha diversity, and strengthened the competitive advantage of Ascomycota. In conclusion, the integration of straw returning and lime application effectively alleviated soil acidification, optimized soil chemical properties and microbial community structure, and promoted stable rice production, offering a efficient and feasible approach for acidic soil remediation in South China.