Abstract: The No. 1 Central Document serves as the overarching policy framework for China’s agriculture, rural area, and farmers (“san nong”). Its evolution over the years delineates the fundamental trajectory of the nation’s food security governance. This study took the 23 No. 1 Central Documents issued from 2004 to 2026, all cebtering on “san nong” theme, as its research object. Employing qualitative research and quantitative text analysis methods, it systematically examined the evolutionary characteristics of China’s food security policies. The findings revealed that: (1) Food security policies encompassed multiple dimensions, including production capacity building, support and protection, reserve regulation and control, accountability and regulation, and supply optimization. The scope of these policies had been progressively refined, and the policy core had shifted from singular focus on “guaranteeing output” to “ensuring security, optimizing structure, and enhancing resilience”. (2) The evolutionary process of food security policies could be divided into three stages: strengthening agriculture and consolidating production, transitioning toward quality improvement and efficiency enhancement, and deepening production capacity security. These phases exhibited progressive and continuous intensifying characteristics. (3) Policy instrument analysis showed that supply-oriented and environmental-oriented instruments had long dominated, while demand-oriented instruments accounted for a relatively low share. However, with the establishment of whole-industrial-chain standards in recent years, the synergy among the three types of instruments had been steadily reinforced. On this basis, this paper proposes recommendations such as addressing demand-side deficiencies, deepening supply-side structural reform, enhancing supply chain resilience, and constructing a diversified food supply system.