Leaf width is one of the key determinants of plant architecture, and optimal leaf width is important to improve the light energy utilization efficiency and the yield production in rice. Identification of the new leaf width mutant and elucidation of its function is of interest to reveal the regulation mechanism. This study reported the zhaiye1 (zy1) mutant, which showed narrow leaf, reduced plant height, shortened panicle, opened spikelets and narrow-thin grains if compared with wild type (WT). The narrow leaf phenotype in zy1 is resulted mainly from the decrease in the number of large veins and small veins. Segregation analysis in a F2 population suggested two independent loci modulating the narrow leaf phenotype, which were further allocated to the regions of 76kb on chromosome 11 and 150kb on chromosome 12, respectively. Tow candidate genes Os11g01130 and Os12g01120 are duplicate genes and encode for the OsWOX3A transcriptional activator. The fusion protein stacking ZY1 with a C’-terminal in-frame GFP was localized to the nucleus in rice protoplastsm, while ZY1 was phylogenetically clustered with the homolog of O. meyeriana. In zy1 mutant, the transcriptome analysis revealed abundant genes in multiple signaling pathways (e.g.auxin signaling pathway). Collectively, these results suggested that ZY1 was involved in the development of leaf width as well as the regulation of plant height, panicle type, glume shell and other traits.