In this study, the nrl2(1), a narrow-leaf mutant of indica two-line sterile line Y58S was used to study the nrl-allete function. Compared with the wild type, the mutant showed mainly the characteristics of narrow and curly leaves, abnormal development of vascular bundles and the numbers of large and small veins were significantly reduced. Genetic analysis indicated that the narrow leaf phenotype was regulated by a pair of recessive nuclear genes, and the target gene was further located in the 46 000 bp region of chromosome 3. The results of map cloning and candidate gene verification indicated that the target gene was an allele of NRL2. Sequencing comparison results showed that the mutation site was the base C in 17th exon of wild-type changed to T, and the corresponding amino acid changed from glutamine into termination codon, resulting in premature termination of translation. Thus, the novel two-line sterile lines with narrow leaves, compact plant type and more tillers could be bred by using nrl2(1) as parent material.