Abstract: This study investigates the impacts and mechanism of high-standard farmland construction policies on carbon emissions from farmland use. It provides significant guidance for optimizing China’s high-standard farmland construction policies and ensuring healthy, green, and low-carbon utilization of farmland resources. Based on panel data from 30 Chinese provinces spanning 2006–2021, this study quantifies total carbon emissions from farmland use and employs a continuous difference-in-differences model to examine the policy’s impacts and underlying mechanism. Results show that: 1) The high-standard farmland construction policy significantly suppresses carbon emissions from farmland use and the conclusion remains robust after a series of stability tests; 2) Mechanism analysis indicates that reducing fertilizer application intensity and agricultural energy consumption intensity are key mechanisms through which the policy effectively curbs increases in carbon emissions from farmland use; And 3) heterogeneity analysis indicates that the suppression effect of the policy is more pronounced in dryland and paddy field cultivation zones, as well as in non-major grain-producing regions. Accordingly, governments at all levels should continue to strengthen policy support for high-standard farmland construction and further explore synergistic mechanisms between agricultural factor inputs and this policy.