Abstract: Through the Shen zhou No. 8 spacecraft carrying a good quality rice varieties of Guangdong Province Yue nong si miao, we obtained a stable spike-type mutant cl, named Yue Hua Zhan 1 Hao, which was applied for new plant species rights of the Ministry of Agriculture in 2015( Application number: 20151728.8; Bulletin number: CNA014491E). The mutant had similar agronomic characters with wild type, but abnormal inflorescence structure, with increased primary branches number, seriously shortened secondary branches and spikelets, clustered 3 spikelets on the branch top.Futher cytological observations suggested that the differences were mainly from the third stage to the fourth stage development of young spike differentiation. Genetic analysis showed that the trait was controlled by a pair of semi-dominant gene, and the gene was initially located on chromosome 6, named CL-6(clustered spikelets). The results of this study were lay the foundation for further fine positioning and cloning CL-6 gene, and reveal the functional gene or regulatory factor of rice spikelet elongation and shorten , at the same time offering excellent germplasm to cultivate the ideal panicle rice and ornamental agriculture.