Main grain producing areas are the main supply base of agricultural products in China. Ensuring the high-quality development of the agricultural economy in the main producing areas is of great significance for doing a good job in food production and building a livable, business-friendly and beautiful village. Based on a panel data of 13 major grain producing areas from 2010 to 2020, this paper calculated the high-quality development level of agricultural economy in major grain producing areas and explores its regional differences and spatial distribution patterns by the entropy method, Dagum Gini coefficient and decomposition method, ArcGIS data visualization function, and exploratory spatial data analysis method. Results show that the high-quality development level of the agricultural economy in major grain-producing areas is on the rise in time; and in space, it shows a slow transition from the middle-low level area to the middle-high level area, and the gradual advancement from the northeast region to the south-central region. The characteristics of spatial agglomeration are gradually weakening. The regional differences within the three major regions are continuously decreasing, but the inter-regional differences are still the main reason for the unbalanced development of agricultural economy. Therefore, to promote the sustainable development of agricultural economy in major grain-producing areas, this paper suggests: focusing on optimizing the efficiency of agricultural ecology, makeing overall plans for the development of agriculture and rural areas in various regions, and making full use of the radiation effect of high-level economic areas.