Using "Qianmilong" pitaya as the experimental material, this study investigates the effects of pineapple waste plant mulching on the physicochemical properties, enzyme activity, soil microbial community structure diversity of the pitaya rhizosphere soil, and the fruit quality of pitaya, aiming to provide a theoretical basis for the research on mulching cultivation techniques in pitaya orchards. The results indicate that: (1) mulching treatment was beneficial to the accumulation of organic matter content, soil water content and nutrient content in the inter-root soil of dragon fruit, and significantly increased the activities of nitrate reductase, urease, cellulase and sucrase, which had a significant enhancement on the yield and quality of dragon fruit ; (2) the mulching treatment caused changes in the structure of soil bacterial community, and the changes of fungal community were not obvious, and the green curvature phylum, actinomyces phylum, morphology phylum, and acidobacterium phylum had a significant influence on the quality of dragon fruit. The relative abundance of the bacterial phylum Green Curvature, Actinomycetes, and the fungal phylum Acidobacteria was significantly increased by mulching, and the relative abundance of the bacterial phylum Green Curvature, Actinomycetes, as well as the fungal phylum Ascomycetes and Acidobacteria was reduced; 10 core bacterial microbiomes and 10 core fungal microbiomes were identified respectively, among which the bacterium Vermicellioides and Actinobacteria phylum and the higher abundance of fungi Coccidioides phylum and Tephritobacterium phylum; Alpha diversity analysis showed that mulching significantly increased the diversity index and evenness index of soil fungi, and did not have a significant effect on the abundance, diversity, and evenness of soil bacteria; (3) KEGG predictive analysis of soil microbial functions reveals that mulching significantly increases the relative abundance of chemoorganotrophy and aerobic chemoorganotrophy pathways in bacterial communities, significantly increases the abundance of various saprophytic fungi, and significantly reduces the abundance of plant pathogens. In summary, the mulching of pineapple waste plants significantly affects the soil physicochemical properties, enzyme activities, and microbial community structure of dragon fruit. It also enhances the soil microbial diversity and relative abundance to varying degrees, thereby promoting the growth and development of dragon fruit plants, increasing the fruit yield, and improving the intrinsic quality of the fruits. The research findings will provide a theoretical basis for optimizing the intercropping model of dragon fruit orchards in Guizhou and enhancing soil quality and microbial functions through improved cultivation techniques.