Rice blast disease, caused by the ascomycete fungal pathogen M.grisea (Hebert Barr, is a world-widely problem in rice growth and production.The rice blast system is a classical genefor-gene system, and previous studies confirmed that gene-for-gene theory plays a pivotal role in explaining HR (hypersensitive response) of host-pathogen relationship, so identification and dynamic distribution analysis of Avr-genes are important for plant disease control.In this study, Avr1-CO39, Avr-pii and Avr-pia were undetectable in the fungus, because they might have been weeded out during the evolutionary process.However Avr-pik, Avr-pita and AvrPiz-t were found in all tested fungus with varied sequences.Firstly, the AvrPiz-t sequences in most of the tested fungus were same to those reported in NCBI, while there was one strain with AvrPiz-t gene sequence missing one base pair.and pathogenicity assay showed that the pathogenic ability was stronger than others.On the whole, AvrPiz-t is evolutionarily stable.Secondly, five genotypes of Avr-pik were detected in all 32 tested fungus, pathogenicity assay showed Avr-pik-B,-F,-G had strong virulence ability comparied with Avr-pik-D.Avr-pita had seven genotypes and all the seven genotypes could be recognized by resistant gene (Pita).According to this study and previously reported data, the rice varieties which carry Pik, Pita and Piz-t alleles will play an essential role in antagonism to the epidemic fungus of rice blast in the Northern China.