Abstract: To investigate the association between differences in resistance to grape downy mildew and endophytic bacterial communities in leaves, 16S rDNA high-throughput sequencing technology was employed to compare the diversity, composition, and structural differences of endophytic bacterial communities in healthy leaves of 6 grape varieties. The results showed significant differences in species richness and community structure among the 6 varieties. Among them, the number of unique OTUs, species richness, and community diversity of the disease-resistant variety 'Shine Muscat' were significantly higher than those of the susceptible variety 'Sweet Sapphire'. Disease-resistant varieties enriched potential disease resistance-related genera such as Sphingomonas, Flavobacterium, Pantoea, and Bacillus. LEfSe analysis indicated that differential species were specifically enriched in two disease-resistant varieties. Among them, o__Enterobacterales, f__Halomonadaceae, Candidatus Portiera, and o__Oceanospirillales were significantly enriched in 'Shine Muscat'; while fewer specifically enriched species were detected in 'Black Emperor', with only o__Rickettsiales identified. This study suggests that the enrichment characteristics of specific genera in the endophytic bacterial community of grape leaves are closely related to downy mildew resistance, and different disease-resistant varieties may enhance resistance through specific microbial communities.