Abstract: Cultivated land is the lifeblood of grain production. Optimizing the ‘trinity’ protection pattern of cultivated land is the need to consolidate the resource base of food security in China. This paper briefly analyzes the evolution background and explains era meaning of the ‘trinity’ protection system of cultivated land in quantity, quality and ecology, dialectically analyzes the logical relationship and delimitation priority of the three control lines, clarifies the planning path and strategy for the optimization of cultivated land ‘trinity’ protection pattern, deeply considers the relevant problems, and puts forward corresponding suggestions.