To clarify the pathogenicity differentiation of Magnaporthe oryzae in the generally susceptible variety Lijiangxintuanheigu （LTH）, 7 Chinese traditional differential varieties and 30 anti-blast monogenic lines were inoculated respectively with 100 single spore strains isolated from Lijiangxintuanheigu. According to the inoculation results , the composition of physiology races, the types of dominant races, virulence and avirulence genes of Magnaporthe oryzae were found. The above results were compared with the pathogenicity of Magnaporthe oryzae from other cultivars in the one region, and it showed that the pathogenicity differentiation of Magnaporthe oryzae from Lijiangxintuanheigu was similar to those isolated from other varieties in the area. The population composition of Magnaporthe oryzae from Lijiangxintuanheigu was ZA（85.00%）,ZB（13.00%）,ZC（2.00%），dominant races were ZA1, ZA5, ZB13; the average virulence was 83.33%. And the population composition of Magnaporthe oryzae from other cultivars were ZA（53.85%）,ZB（38.46%）,ZC（5.77%）,ZD（1.92%）; dominant races were ZA1, ZB15, ZB13; the average virulence was 78.01%. So the study of monitoring physiology races of Magnaporthe oryzae was of great reference value in the identification of resistance genes of rice cultivar and acquisition of rice blast samples.