Abstract: 【Objective】 Citrus canker caused by Xanthomonas citri subsp. citri (Xcci) is one of the most important plant diseases.The aim of the experiment was to study the genetic diversities of Xac in Guangdong and Jiangxi Provinces.【Method】The bacterial strains which were collected from 12 cities (counties) of Guangdong and Jiangxi Provinces on 12 varieties were investigated with ERIC-PCR．Dendrograms were generated by NTSYS software according to fingerprint features.【Result and conclusion】 The results indicated that 71 Xac strains could be clustered division A and B.All the strains from Jiangxi Province were distributed on division A, while half of the strains from Guangdong Province were distributed on division B. Both division A and B could be seperated into 6 groups at a level of 88% similarity respectively. There were significant genetic diversities of Xac strains from Guangdong and Jiangxi Provinces. It showed that the diversity differences of strains from different geographical origins or different varieties were significant.