Abstract: Food security is a research hotspot at home and abroad. At present, global food security is facing serious challenges and the prospect is not optimistic. As the biggest country of population and food consumption in the world, China is confronted with greater challenges in food security, for which there exist debates in Chinese academia. In order to accurately understand the connotation of food security to scientifically evaluate China''s food security status, changes in the concept of food security were firstly analyzed, and then food demand balance indicators, consumption indicators, nutrition indicators, comprehensive indicators, as often used to evaluate food security, as well as the general indicators for evaluating grain safety were summarized. With improvement of people''s living standard, food structure in China has changed fundamentally, thus, the food security research in the future should be transformed from focusing on only grains to whole food system by including all kinds of food, with more attention paid to the assessment of comprehensive food guarantee capability and nutrition security.