Over the past few years, organic agricultural management models that comply with scientific standards have been acknowledged as more sustainable agricultural practices than conventional ones. However, the long-term and sustained impacts of organic management systems require thorough investigation, especially focusing on soil microbial community diversity, changes in microbial community composition, soil properties, and tea quality. Based on this context, the present study addresses two core research questions: first, how do long-term organic and conventional management differ in tea garden ecosystems? Second, how does sustained organic management regulate tea garden soil characteristics, soil microbial community structure and diversity, and tea quality? To answer these questions, soil samples were collected from organically managed tea gardens with 5, 15, and 20 years of management history, as well as from conventionally managed tea gardens for comparative analysis. A combination of physicochemical property testing and metagenomic techniques was employed to systematically analyze and compare the soil samples. The results showed that sustained organic management in tea plantations could effectively mitigate soil acidification, maintaining soil pH in the range of 5.6-6.3, which is the optimal range for tea plant growth. It significantly increased soil organic matter content by 1.3-2.2 times, and enhanced the contents of multiple soil nutrients, including alkaline-hydrolyzable nitrogen, exchangeable calcium, and exchangeable magnesium. Meanwhile, continuous organic management significantly improved tea quality. Specifically, it elevated the contents of tea polyphenols, free amino acids, and water-soluble extracts, while optimizing the polyphenol-to-amino acid ratio. Principal component analysis revealed statistically significant differences in soil bacterial community structure between organically and conventionally managed tea gardens. Furthermore, continuous organic management not only increased the species richness and diversity of tea garden microbial communities, but also promoted the convergence and stability of the microbial community structure. At the phylum level, Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi were the dominant phyla in both sustainably and conventionally managed tea garden soils, indicating a certain degree of homogeneity in soil microbial community composition. In contrast, long-term, sustained organic management enhanced the abundance of microorganisms involved in disease suppression and nitrogen cycling in tea garden soil, while reducing the abundance of pathogenic bacteria. Based on the results of redundancy analysis, soil parameters including total potassium, pH, organic matter, exchangeable magnesium, exchangeable calcium, total nitrogen, available phosphorus, cation exchange capacity, and alkaline-hydrolyzable nitrogen. These parameters have been identified as the environmental factors that have the most significant impact on the bacterial community. Overall, compared to the conventional management model, the long-term continuous organic management model has had positive effects on tea garden soil. Specifically, it not only increased the content and availability of beneficial nutrients in tea garden soil, but also promoted the formation of beneficial microbial structures. This, in turn, shaped soil bacterial assemblages conducive to tea plant growth, thereby significantly improving tea quality.