<p>Assessing the impact of Agricultural Heritage Systems (AHS) policy on the county economy is significant for achieving a balance between the protection of traditional agricultural culture and economic development. Taking 1851 county-level administrative units in China from 2000 to 2021 as samples, this study systematically analyzed the impact of the identification of AHS on the county's economic development by using the DID model. The results show that: (1) The AHS policy has a positive effect on the economic development of counties. Among them, the Globally Important Agricultural Heritage Systems (GIAHS) have the greatest impact on economic growth, followed by the National Important Agricultural Heritage Systems (NIAHS). (2) The AHS fosters county-level economic growth through brand effects and the cultivation of economic agents. In addition, the AHS has contributed to the increase in rural incomes and the optimization of regional industrial structures. (3) The NIAHS policy can promote the economic development of originally impoverished counties, counties with higher fiscal expenditure, and counties with better ecological environments. The GIAHS policy has a positive impact on all types of counties and districts, but its promoting effect is greater on the original impoverished counties, counties with higher fiscal expenditure, and counties with better ecological environments. Future policymakers can promote economic development in heritage areas by strengthening the excavation of cultural heritage, guiding and supporting the development of regional brands in AHS counties and districts, and supporting the growth and expansion of various agricultural entities in AHS counties and districts.</p>