China is the world's largest food producer, and it also has the largest food demand. The stability of China's food production directly affects the supply and demand situation of the world food market. In the context of evolving Chinese agricultural structure, this paper studies the separation of factors of production from grain and issues concerning food safety. It is found that the arable land for food production within agricultural sector continues to flow to non-food production sector while the arable land is shrinking in China; the process of urbanization of population is the main reason for food production workforce reduction, resulting in a decline in the overall quality of the food production labor. By analyzing the panel data estimation results for food production function, it is found that arable land and labor are still important factors for food production in China at present, and their flow out of food production poses a major threat to food production and security.