Abstract: Grafting was found effective in enhancing plant disease resistance. Rhizosphere microbial communities play a crucial role in plant resistance to soil-borne diseases. Eggplants and tomato were used as rootstocks and scions，respectively，to investigate the impact of grafting on soil biochemical properties and bacterial community composition in tomato rhizosphere. We found that grafting significantly increased cultivable bacteria，actinomycetes，microbial biomass-C，N and P，and enzyme activities in tomato rhizosphere. Higher bacterial richness，evenness and diversity indices were also observed in the rhizosphere of grafted plants compare to self-rooted plants. High-throughput sequencing revealed that norank_c_Acidobacteria，Nitrospira，Bacillus，norank_f_Gemmatimonadaceae，norank_o_Gaiellales，norank_f_Xanthobacteraceae，norank_o_SC-I-84，norank_f_Anaerolineaceae，norank_f_Nitrosomonadaceae and Sphingomonas were dominant bacterial genera，which were found common in rhizosphere of grafted and self-rooted plants. The g_unclassified_o_Ignavibacteriales，g_Acetobacter，g_norank_f_ Longimicrobiaceae，g_unclassified_f_Verrucomicrobiaceae，g_norank_p_FBP，g_norank_p，and Aminicenantes were specific dominant bacterial genera found only in the rhizosphere of grafted plants. Our results indicated that tomato grafted on eggplant promoted soil nutrition availability by increasing culturable microorganisms，microbial biomass and related enzyme，activities in tomato rhizosphere. At the same time，it has different dominant proportions of the common bacterial genus,especially greater number of bacterial total OTU and endemic OTU，which is the main reason for the increased resistance of grafted plants.

Key words: tomato, grafting, soil biological properties, bacterial community structure, high throughput sequencing