A rice shortroot mutant Osksr6 was identified from an ethylmethane sulfonate (EMS)mutagenized rice library. Phenotypic observation, genetic analysis and gene mapping analysis of Osksr6 were carried out. Results showed that: (1) at the 7 d old stage, there was no significant difference in plant height and the number of adventitious roots between the wild type and Osksr6, while the length of primary and adventitious roots of Osksr6 was decreased by 61.98% and 46.42% compared with the wild type, respectively. Furthermore, the development of lateral roots and root hairs in Osksr6 was also inhibited to varying degrees. At the maturation stage, the tiller number of Osksr6 significantly decreased, and the panicle length and seed rate of Osksr6 were also reduced. (2) Genetic analysis showed that the mutant phenotype was controlled by a single pair of recessive nuclear gene. (3) Mapbased cloning analysis located OsKSR6 to a 460 kb region between newly designed InDel markers 28420k and 28880k on chromosome 3. There is no gene reported to be involved in root development in this region. This result will be helpful for the cloning of OsKSR6 and further characterization of molecular genetic mechanisms underlying root architecture in rice.