Abstract: Building a diversified food supply system can stabilize and expand food supply, meet the requirements of people's diversified food needs, and promote the transformation of agri-food system. Adopting the idea of the big food approach, this paper analyzed China's main practices in building a diversified food supply system, explored its shortcomings, and proposed countermeasures for building a diversified food supply system in the future through a systematic review of relevant policies, literature, and data. Results show that China has made great achievements in increasing domestic food production, ensuring the supply of major agricultural products, participating in international agricultural trade, and establishing a vision of big agriculture and big food approach. However, there are obstacles that limit the diversified food supply, including the mismatch between the supply of agricultural products and consumer demand, insufficient diversification of food consumption, unbalanced regional layout of domestic agricultural production, over-concentration of foreign agricultural imports, and lack of diversification of agricultural processing products. In order to better build a diversified food supply system, the government should adopt a big food approach to coordinate the production of grains and other major agricultural products, enrich and optimize the structure of food production and consumption, broaden and expand food sources, reasonably lay out the production areas of agricultural products, expand the whole industrial chain of the agri-food system, and make good use of both domestic and international markets and resources.