Increase of crop production is the primary goal of crop breeding. Rice grain shape is a quantitative trait that is directly related to yield traits and has a close relationship with quality traits. The evaluation of grain shape is mainly grain length, grain width, grain thickness, length/width, and length/thickness. In recent years, the quantitative genetic research on rice grain shape has made a significant progress and a number of important genes associated with rice grain shape have been cloned. This paper reviews the classic genetic analysis on rice grain traits, QTL mapping, grain shape gene cloning and functional analysis, and their application in rice breeding for super high yield.