As the basis for maintenance of national security and global strategic material, food has always captured the attention of governments in the world. After reaching a certain stage of industrialization, most countries will take the food support and protection measures, and the policy objectives and policy tools have evolved into a set of policy systems through continuous adjustment, but the intervention in food price has always been present. The food price intervention only plays a role in regulating food market supply and demand and guaranteeing minimum income for grain producers, and it can not reflect the cost of food production and continuously improve grain producers' income, but because of its simple operation, low cost and immediate effect, it is suitable for the countries with a large number of grain producers but small operation scale in the short term.