Rice is the most important food crop in China. During the period of 1974, archaeologists excavated a large number of rice, rice husk and rice leaves at the Neolithic site in Hemudu, Yuyao County, Zhejiang Province. Rice hulls and rice leaves keep their original shapes, some rice leaves are as new in color, and some rice hulls are even clearly distinguishable from rice hairs. It has been identified that these rice grains have a history of 6700 ~ 6900 years and are the earliest existing rice grains in the world.