This study aims to elucidate the effects of exogenous additives on the rhizospheric microenvironment of rice and their subsequent influence on Cd accumulation. Biochar (BC) and arbuscular mycorrhizal fungi (AMF) were utilized as representatives of abiotic and biotic agents, respectively, jointly added to modify the rice rhizosphere in response to soil Cd contamination. Results show that the incorporation of both biochar and AMF significantly enhanced the soil organic matter content, thereby exerting a positive impact on the levels of available phosphorus, available potassium, and soil carbon-nitrogen fixation. Furthermore, these additives mitigated the inhibitory effects of Cd stress on soil urease activity, resulting in an increase in the proportion of DTPA-extractable Cd from 58.95% to 64.42%. Cd stress significantly influenced the richness and diversity of the microbial community within the rice rhizosphere soil. The addition of biochar and AMF facilitated the recovery of the abundance of the proteobacteria phylum, increasing from 29.7% to 33.1%. At the 1 mg/kg soil Cd, the abundance of the Bacillus community in the BC+AMF treatment group increased by 88.5% compared to the CK treatment group. Under a stress condition of 5 mg/kg soil Cd, the synergistic application of biochar and AMF resulted in an increase in the proportion of Cd accumulation within the rice root system, rising from 60.4% in the CK group to 77.1% in the BC+AMF treatment group, concurrently reducing the proportion of Cd accumulation in the seeds from 4.4% to 1.6%. The addition of biochar and AMF improved the nutritional conditions and the structure and functionality of the microbial community in the rice rhizosphere soil, thereby facilitating the sequestration of Cd within the rice root system and diminishing its translocation to the aboveground seeds. These findings offer substantial theoretical support for the integrated application of biotic and abiotic factors in the remediation of heavy metal-contaminated soil environments.