The fungus, Magnaporthe grisea of rice blast colonizes leaves (leaf blast), panicles (panicle blast) and other parts of the rice plant, and causes significant yield loss in rice-growing areas worldwide. One of the most effective means of controlling rice blast disease is the development and use of resistant rice cultivars; however, newly developed resistant cultivars often lose their resistance after a few years of commercial production. Pyramiding major genes, accumulating QTLs, and combining major and minor QTLs have been considered to develop the durable resistant rice to blast. This study was carried out to analyze the resistant QTLs to blast in the japonica rice. In the QTLs analysis related with resistance to the inoculation of isolates and field screening, we identified a significant putative QTL at RM317-OSR15 region on chromosome 4 in regionly and yearly in common. This QTL explained 8.4-14.9% of total phenotypic variation for each character of isolate screening and blast nursery test. Alleles from Suweon365, GL33 and Moroberekan increased the level of resistance in this QTL. This QTL is the same as or similar to those from Japanese upland rice, Kahei (Miyamoto et al. 2001). A QTL from Suweon365 on chromosome 4 The BC2F2 lines with the Suweon365's QTL region RM255-RM349 on chromosome 4 were developed from the backcross with Chucheongbyeo (susceptible, degree 8) were the incidence degree 6±1.02 at blast nursery. BC2F2 lines having the Moroberekan's QTL region RM317-OSR15 on chromosome 4 developed from the backcross of Ilpumbyeo (susceptible, degree 7-8) were the incidence degree 4±1.45 at blast nursery. We are discussing for the constructing of the fine map and searching the candidate genes in this region, and the allelic effect of QTL-NILs.