【Objective】Ralstonia solanacearum, a highly virulent plant pathogenic bacterium, causes bacterial wilt in tomatoes and other crops, leading to host death and significant yield losses, posing a serious threat to agricultural economies. The rhizosphere, as a critical environment for plant-microbe interactions, plays a decisive role in determining the outcome of pathogen invasion and plant health. However, the interactions between bacteria and fungi in the rhizosphere under pathogen invasion remain unclear, limiting our understanding of the microbial changes associated with bacterial wilt disease.【Method】In this study, we aimed to investigate the impact of R. solanacearum invasion on the composition and interaction networks of bacterial and fungal communities in the rhizosphere of diseased and healthy tomato plants. We utilized quantitative real-time PCR (qPCR) to quantify microbial abundances and high-throughput amplicon sequencing to characterize the diversity and structure of bacterial and fungal communities. By comparing the microbial co-occurrence network in rhizosphere soils of diseased and healthy tomato plants, we sought to elucidate how pathogen invasion affects the microbial community structure and their ecological interactions.【Result】The results showed significant differences in the bacterial communities between the rhizospheres of diseased and healthy plants. The rhizosphere of diseased plants was invaded by a higher abundance of R. solanacearum, while the rhizosphere of healthy plants was significantly enriched with bacteria from the phyla Actinobacteria and Firmicutes, which include a greater number of beneficial bacteria with potential for biological control. Moreover, pathogen invasion reduced the ecological niche breadth and qPCR counts of fungi in the rhizosphere. Co-occurrence network analysis revealed that the bacterial-fungal network in diseased rhizospheres was more complex, with a significantly higher proportion of fungal nodes (46.7% compared to 31.0% in healthy rhizospheres). Among them, Ascomycota species emerged as key network nodes, indicating that pathogen invasion enhanced the close associations between bacteria and fungi (particularly Ascomycota species). In the direct bacterial-fungal interactions, the proportion of negative correlations in diseased rhizospheres (46.3%) was notably higher than in healthy rhizospheres (35.4%), suggesting that pathogen-induced interactions were predominantly antagonistic. Additionally, in the bacteria-fungi networks, Ascomycota and Actinobacteria were identified as key fungal and bacterial taxa, serving as biological indicators in diseased and healthy rhizospheres, with significant positive (R2 = 0.393, P = 0.002) and negative (R2 = 0.523, P = 0.0002) correlations with pathogen abundance, respectively.【Conclusion】This study elucidates the disruptive effects of R. solanacearum on rhizosphere microbial communities, particularly the bacterial-fungal ecological interactions, and highlights the changes in rhizosphere microbial structures under bacterial wilt. These findings provide a theoretical foundation for developing future strategies to control bacterial wilt in tomatoes.