China's commercial rice can be determined according to enterprise standards, local standards and national standards. When the rice quality grade standard in enterprise standards and local standards is lower than the national standard, the rice grade is determined according to the national standard.

According to national standards, rice in China is divided into three categories according to the classification method of rice: indica rice: including early glazed rice and late indica rice; Japonica rice: including early japonica rice and late japonica rice; Glutinous rice: including indica glutinous rice and japonica glutinous rice.

All kinds of rice in China are mainly classified according to processing accuracy. Processing accuracy refers to the peeling degree of brown rice when it is processed into white rice. Different grades of rice have different degrees of peeling during processing. The national standard GB 1354-86 divides all kinds of rice into four grades. As far as processing accuracy is concerned, the top grade rice: there is skin on the back ditch, and the grain surface rice skin is basically removed, accounting for more than 85%; Standard first-class rice: there is skin on the back ditch, and the skin on the grain surface does not exceed 1/5, accounting for more than 80%; Standard second-class rice: there is skin on the back ditch, and the skin on the grain surface does not exceed 1/3, accounting for more than 75%; Standard third-class rice: there is skin on the back ditch, and the skin on the grain surface does not exceed 1/2, accounting for more than 70%.

The classification of all kinds of rice should also refer to the following indicators:. ① Imperfect grains: including immature grains, insect-eaten grains, diseased grains, moldy grains and intact brown rice grains without peeling at all; (2) Impurities: including bran powder, minerals (sandstone, cinder, bricks and other minerals), barnyard grass grains with shells, rice grains and other impurities (rice grains, foreign grains and other substances with no edible value). The total allowable impurity content of all grades of late japonica rice is lower than that of other types of rice.

The national standard also determines ① yellow rice (grains with yellow endosperm and obviously different color from normal rice grains) contained in all kinds of rice; ② Broken rice: including big broken rice and small broken rice; ③ moisture; (4) color, smell and taste (referring to the inherent comprehensive color, smell and taste of rice) are required, but for the same variety and different grades of rice, the above four indicators are equivalent.

For rice that can't meet the grade quality requirements, it should be degraded. At present, the rice sold in China's grain market is mainly standard first-class rice and special-class rice.