Abstract: The Pseudomonas solanacearum（tomato bacterial wilt） is one of the most serious diseases in tomato production in Guizhou province. In order to clarify the genetic diversity of P. solanacearum isolated from Guizhou province, the carbohydrate utilization, pathogenicity, 16 SrDNA sequences, evolutionary types and Sequence variations of the 8 P. solanacearum isolated from Guizhou province were analyzed, and the resistance of rootstocks from 17 tomato varieties to P. solanacearum in Guizhou province was also evaluated.The results showed that 8 strains of P. solanacearum belonged to physiological strain No.1 of Ralstonia solanacearum and biochemical variant No.3.Molecular biological analysis further showed that 8 strains of P. solanacearum belonged to evolutionary type I,with sequence variants 17 and 54.And, the rootstocks of 17 tomato varieties were identified by artificial inoculation and the results showed that the disease incidence of 17 rootstocks from varieties ranged from 13.66% to 100%.Among them, 6 rootstocks showed high resistance to tomato bacterial wilt and 4 rootstocks showed resistance to tomato bacterial wilt, while 2 rootstocks showed tolerance to tomato bacterial wilt and other 5 rootstocks showed susceptibility to this disease.