Abstract: Rice (Oryza sativa) is one of the most important food crops in the world and a model plant for study of molecular developmental biology in monocots. Panicle morphology is an important component of rice production and has become a “hot” topic in genetic improvement and developmental biology research of rice. Multiple-grain rice is a mutant of spikelets, which can be divided into clustered-spikelet and multi-pistil types created by natural mutation, hybrid variation, and physical/chemical mutagenesis. As a new germplasm resource, multiple-grain rice can help to establish new materials, new varieties, and sterility propagation and help in research into mechanisms of rice flowering. Because of spike grain density, multiple-grain rice can be used for large-compound-grain rice breeding materials, improving spike grain density and grain number per spike, shortening spike length, ameliorating rice plant traits, enhancing resistance and increasing yield. Here, we summarize the features of multiple-grain rice, origin, genetic analysis, gene location and breeding utilization, and point out the future of this research, which should provide a reference for further researching multiple-grain rice.