Abstract:One hundred and thirty-seven isolates of rice blast fungus collected from six long-grained nonglutinous rice-growing regions in Sichuan Province of China were analyzed for DNA polymorphism by using rep-PCR technique. There were 73 different DNA fingerprints (haplotypes), 62 different DNA bands and 37 genetic lineages at 0.19 similar linkage distance level. The results showed that the rice blast population of Sichuan included predominant lineages and many small and distinctive diversified lineages, which indicated plenty of genetic information among them. Furthermore, the rice blast population in Sichuan was exhibited obvious spatial and temporal characteristics, and in three years all isolates exist relative relationship and special lineages for each year while in different rice-growing regions they changed from relative simple to complicate. The rice blast population was closely related to the host genetic background and no distinctive correlation with pathotypes. It was no meaning with genetic lineages in contrast to pathotypes so far.