Abstract: China's food self-sufficiency ratio gradually reduced that has touched the red line of White Paper on food safety, which implies the great pressure on China's food security nowadays. For this issue, domestic theorists and government have attacheed great importance. This article refers to the concept by economist Lin Yifu viability referred to grain and other crops as a comparative analysis of different industries, finally it gets the main root cause of the problem is due to the surplus of rural labor. To deal with this problem, we tries to give some reasonable policy suggestion. First, we should renovate the rural infrastructure, then encourage the creation of township enterprises, increase the production of high quality food and so on.