Abstract: A clustered spikelets mutant(Cl-dz) controlled by single recessive gene was found in the progeny of a rice breeding material, its phenotype characteristic was that 2 or 3 spikelets cluster on the second stem in the shape of "W". Genetic analysis indicated that the trait was a recessive trait genetically controlled by single gene. The F2 mapping population was constructed by hybridization between mutant Cl-dz and G46. And the gene Cl-dz was mapped between SSR markers, RM6036 and RM1340 in chromosome 6 of rice. The genetic distance was 3.6 cM and 7.0 cM, respectively.