Abstract: Scientifically adjusting and delineating grain production and consumption areas is essential for optimizing the allocation of grain policy resources and fully realizing grain production potential. In 2004, China designated 13 major grain producing areas that remain in place today. Over the subsequent two decades, however, the relationships between grain production and consumption in some of these areas have changed substantially. The number of provinces capable of generating net grain outflows has declined, their spatial distribution has become increasingly concentrated, and some major grain producing areas have effectively transitioned into regions with a balance between grain production and consumption. To more accurately identify major grain producing areas and improve policy precision, this paper proposes a new classification framework based on data from 2004 to 2024. This framework comprehensively evaluates three core indicators: cultivated land area, the alignment between grain production and population, and net grain outflow volume. Based on this, this paper recommends establishing a dynamic adjustment mechanism for major grain producing areas, strengthening policy support for newly identified major grain producing areas, that have become net grain importers. These measures are intended to establish a more targeted, efficient, and adaptive policy support system for major grain producing areas.