Through QTL（Quantitative trait loci）affecting main rice quality characters and indica-japonica differentiation were analyzed by using of a recombinant inbred （RI）lines derived from a cross of Asominori×IR 24 and its RFLP map wity 293 molecular markers by single marker analysis and interval mapping.Nine QTLs for grain shape traits were detected in this population,three of them（R11,R12 and R13）were that controlled grain length,two（Rw1 and Rw2）controlled grain width,four（Lw1,Lw2,Lw3 and Lw4）controlled grain length/width.It were indicated that grain length were affected multi-gene,grain width were affected two main-effective genes and some mini-effective genes,grain length and grain width were quantitative traits.Grain length and grain width were independent inherit traits.