Forty–nine main rice cultivars of Jiangsu were tested for resistance to rice blasts by inoculating through spraying in seedling stage and by inoculating through injection in booting stage. And 14 molecular markers were used to analyze the genotype and genetic diversity of blast resistance gene. The results showed that no rice cultivar tested exhibited high resistance to leaf blast and neck blast. Among the 49 materials, 5 cultivars exhibited resistance, 7 exhibited moderate resistance, 14 exhibited moderate susceptibility, 12 exhibited susceptibility and 11 exhibited high susceptibility to neck blast; 2 cultivars exhibited resistance, 8 exhibited moderate resistance, 6 exhibited moderate susceptibility, 9 exhibited susceptibility and 24 exhibited high susceptibility to leaf blast. Only 4 cultivars simultaneously exhibited resistance and moderate resistance to leaf blast and neck blast (8.2%). Thirty–five alleles had been tested by 14 molecular markers, variation range of polymorphism information content was 0.000 0–0.537 5, with an average of 0.339 8. Two to eight resistance genes were found for each cultivar, at least five resistance genes were found in 39 materials (79.6 %). The cluster analysis result showed that the 49 cultivars were clustered into 3 groups, and the similarity distance variation range was 0.000 0–0.857 1, with an average of 0.403 9. And 49 rice cultivars dispersed in the clustering figure, indicating frequent exchanges between germplasm resources and high sharing rate of valuable genes.