The evaluation of genetic diversity of 66 Xanthomonas axonopodis pv.dieffenbachiae (Xad) strains from 27 anthurium varieties in 9 cities from Guangdong Province was conducted by Rep-PCR technology. The DNA of Xad was amplified by the primer ERIC and the genetic diversity was evaluated by UPGMA clustering analysis. The results showed that 66 Xad strains could be divided into 14 genetic groups at the similarity level of 0.85, and the genetic group Ⅰ,Ⅱ and Ⅹ were the major groups. It shows that there were obvious differentiation and rich diversity in X.axonopodis pv.dieffenbachiae strains in Guangdong Province.