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 anal-ysis 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 effective-ly inhibit the propagation of tomato bacteria wilt and thus achieve the effect of tomato bacteria wilt control.