Abstract: ObjectiveThe pathotype distribution and differentiation of Xanthomonas oryzae pv. oryzae (Xoo) in Guangxi were ascertained to provide theoretical references for integrated control of rice bacterial blight.Method29 iso-lates from rice production regions of Nanning, Dongxing, Fangcheng, Qinzhou and Cenxi City in 2013 were preliminari-ly evaluated on a set of Chinese differential varieties (Jinggang 30, Tetep, Nanjing15, Java14 and IR26) of Xoo and the pathogenicity of 5 isolates from Nanning was further analyzed using some near-isogenic lines. ResultDisease reac-tion patterns of all 29 isolates on 5 hosts were SSSSS(all susceptible) and the pathogenicity was high. Furthermore, the isolates collected from Nanning could cause rice near-isogenic line CBB23 with broad spectrum highly susceptible .ConclusionGreat differentiation is shown in pathogenicity of Xanthomonas oryzae pv. oryzae (Xoo) in Guangxi. Hence, integrated control of rice bacterial blight and selection of resistant rice materials should be strengthened in the future.