Abstract: In the report， in order to obtain the antagonistic bacteria with inhibitory effects against tomato bacteria wilt， the morphological indicators， physiological and biochemical characteristics， and 16S rRNA sequence analysis were used to study the strains， and three potted tomato soil samples， negative control （CK）， positive stress treatment （RB） and antagonistic bacterium K+ tomato cyanobacteria treatment （KRB） were used to analyze the expression of defense response genes. The results indicated that the antagonistic bacterium K5 colonies were creamy white with smooth surface， Gram-positive， Bacillus， and which were identified as Bacillus velezensis by molecular identification. The inhibitory effects of Pot control of tomato cyanobacteria reached 23.20%， y the K5 strain was able to induce the expression of disease resistance genes in tomato roots 48 h after inoculation， and the expression of CTR and ETR genes were increased， which suggested that K5 induced plant disease resistance through the expression of plant disease-resistance related genes and thus disease resistance， which can effectively inhibit the propagation of tomato bacteria wilt and thus achieve the effect of tomato bacteria wilt control.