Abstract <p>This study investigates the regulatory effects of cultivar and tree age on the rhizosphere bacterial community of <i>Macadamia integrifolia</i>, aiming to provide theoretical support for targeted regulation of the rhizosphere microecosystem and high-quality, high-yield production in the industry. Using rhizosphere soil from 5-year-old and 8-year-old plants of five major cultivated cultivars as materials, the bacterial community characteristics were revealed through 16S rRNA gene high-throughput sequencing combined with R-based data analysis and visualization. The results show that the community is dominated by two phyla, Actinobacteria and Chloroflexi, with the core dominant genus being <i>Rhodoplanes</i>. Cultivar is the leading factor driving community differentiation, and the effect of tree age is cultivar-specific. Functionally, the community is dominated by amino acid, carbohydrate, and lipid metabolic pathways, which are well-adapted to the host plant’s growth demands; the co-occurrence network exhibits predominantly strong positive correlations and high modularity, suggesting synergistic adaptation and metabolic complementarity among dominant bacterial taxa. This study clarified that the rhizosphere bacterial community of <i>Macadamia integrifolia</i> is primarily regulated by cultivar, and has identified core functional taxa such as <i>Rhodoplanes</i>, laying a scientific foundation for the development of specialized microbial inoculants and the coordinated regulation of cultivar-microbe interactions.</p> Key points <p>• <i>Cultivar is the dominant driver of macadamia rhizosphere bacterial community, with tree age exerting cultivar-specific effects.</i></p> <p>• <i>Rhodoplanes is the core dominant genus, and the bacterial community functions are dominated by metabolic pathways.</i></p> <p>• <i>Macadamia rhizosphere bacterial co-occurrence network shows strong positive correlations and modularity, guiding microbial inoculant development.</i></p>