A rice male-sterile mutant OsMS-L of japonica cultivar 9522 background, was obtained in M4 population treated with Co γ-Ray. Genetic analysis indicated that the 60 male-sterile phenotype was controlled by a single recessive gene. Results of tissue section showed that at microspore stage, OsMS-L tapetum was retarded. Then tapetal cells ex- panded and microspores degenerated. No matured pollens were observed in OsMS-L anther locus. To map OsMS-L lo- cus, an F2 population was constructed from the cross be- tween the OsMS-L (japonica) and LongTeFu B(indica). Firstly, the OsMS-L locus was roughly mapped between two SSR markers, RM109 and RM7562 on chromosome 2. And then eleven polymorphic markers were developed for further fine fine-mapping. At last the OsMS-L locus was mapped between the two InDel markers, Lhs10 and Lhs6 with genetic distance of 0.4 cM, respectively. The region was delimited to 133 kb. All these results were useful for further cloning and functional analysis of OsMS-L. A rice male-sterile mutant OsMS-L of japonica cultivar 9522 background, was obtained in M4 population treated with Co γ-Ray. Genetic analysis indicated that the 60 male-sterile phenotype was controlled by a single recessive gene. Results of tissue section showed that at microspore stage, OsMS-L tapetum was retarded. Then tapetal cells were ex-panded and microspores degenerated. No matured pollens were observed in OsMS-L anther locus. To map OsMS-L lo-cus, an F2 population was constructed from the First, the OsMS-L locus was roughly mapped between two SSR markers, RM109 and RM7562 on chromosome 2. And then eleven polymorphic markers were developed for further fine fine-mapping. At last the OsMS-L locus was mapped between the two InDel markers, Lhs10 and Lhs6 with genetic distance of 0.4 cM, respectively. The region was delimited to 133 kb. All these results were useful for further cloning and functional analysis of OsMS-L.