As a crucial technology for global CO₂ reduction, CO₂ capture and storage (CCS) faces leakage risks that endanger surrounding organisms and the environment. This study aimed to clarify how CO₂ leakage impacts the rhizosphere soil's physicochemical properties and microbial communities, supporting CCS environmental risk assessments. A simulation platform was built, and the 16S rDNA high-throughput sequencing, correlation, and redundancy analyses were used to examine soybean cultures. Results showed that as soil CO₂ concentration rose, pH and O₂ significantly declined, while Soil Organic Carbon and Ammonium Nitrogen increased. Total Nitrogen and Nitrate Nitrogen decreased, with the latter dropping notably. Microbial Biomass Carbon and Nitrogen in soybean rhizosphere soil rose at 10% and 30% CO₂ but fell at 50%. CO₂ leakage reduced the Chao1 index of rhizosphere soil bacteria yet increased the Pielou’s evenness index. Although dominant bacterial phyla remained consistent, Bacteroidetes became more abundant, while Proteobacteria, Acidobacteria, and Nitrospirae decreased. O₂ and pH were key factors shaping bacterial diversity and phylum-level community abundance.