Tianjin Grain and Oil Price Index is the first local grain and oil price index in China. Developed, researched and established by Tianjin Grain and Oil Information Center, the Tianjin Grain and Oil Wholesale, Retail and Composite Price Index System has been officially released on "Jin Grain Net" since June 2002, and is released once a month. Tianjin Grain and Oil Price Index includes Tianjin Grain and Oil Wholesale, Retail and Composite Price Index. The wholesale price index includes six indices for wheat, corn, flour, soybeans, soybean oil and salad oil. The retail composite index includes 6 indices: flour, rice, mung bean, soybean, peanut oil and salad oil. Characteristics of the market in the sales area Tianjin is the main grain sales area, with an annual grain deficit of 3 million tons relying on purchases and imports from outside the city. Based on the characteristics of the sales area in Tianjin, we determined to establish two price index systems - namely, the wholesale price index of grain and oil and the retail price index of grain and oil. The purpose of establishing the wholesale price index is mainly to facilitate the analysis and study of the impact of the national grain and oil market on the grain and oil market in Tianjin, as well as to study the relationship between wholesale and retail prices of grain and oil in Tianjin; the purpose of establishing the retail price index of grain and oil is mainly to study the extent of the impact of retail prices of grain and oil on the grain and oil consumer market.