Seventy eight strains of Xanthomonas oryzae pv. oryzae collected mostly from North, Northeast and a few from Center and South China have been assessed the RFLP types for analyzing the population structure and genetic diversity by using two probes, pJEL 101 and pBSavrXa 10. Genomic DNA from each strain of X. o. pv. oryzae was digested to completion by enzymes EcoR I or BamH I for blots probed with pJEL101 or pBSavrXa10. Sixteen RFLP types were identified respectively. Fourteen RFLP types were found in strains of pathotypes 1, 2 and 6, which were from North and Northeast China(using pJEL 101).Among them differed only at one or 3-4 banding positions. In comparison between those with RFLP types of strains from Guangdong and Yunnan provinces were distinct from one another at 7 or 8 positions varied. Cluster analysis based on RFLP banding showed six groupings at 85% similarity. The majority of strains from pathotypes 1, 2 and 6 were grouped in clusters 1. A few strains, LN43, GD1358 and YN5 were grouped in clusters 4, 5 and 6. respectively. The genetic diversities of the population of strains tested was 0.77 (for pJEL101 ) and 0.83 (for pBSavrXa10) respectively. Genetic diversities for each pathotypes tested as a subpopulation has been also calculated. The preliminary analysis here showed that the genetic diversity of X.o. pv. oryzae in China was various. It will be necessary to assess more strains collected from South, Center and Southwest China for analyzing the population constructure and genetic relationship of X.o. pv. oryzae in China systematically.