Abstract: In order to clarify the effects of Pseudomonas lini, Bacillus safensis, Bacillus siamensis and Hypocrea lixii on tobacco black shank (TBS) control and rhizosphere soil microorganisms, pot and field experiments were conducted to investigate the control effects of these strains, and the microorganism diversity of rhizosphere soil was tested by Illumina Miseq sequencing technology. The results showed that: 1) Compared with metalaxyl·mancozeb, P. lini, B. safensis, B. siamensis and H. lixii had better control efficacies in both the pot and field experiments, which were 95.0% and 95.9%, 96.2% and 81.2%, 90.9% and 78.4%, 88.7% and 39.3%, respectively. 2) The microorganism diversity of rhizosphere soil reduced after the treatments with metalaxyl·mancozeb and biocontrol bacteria. The numbers of main bacterial and fungal species presented an increasing trend and a decreasing trend respectively. 3) Although metalaxyl·mancozeb and the biocontrol bacteria did not change the structures of the dominant bacterial and fungal communities, the abundances of microorganisms in soil were different.