<p>Sustainable farmland use is strategically important for achieving “efficient output, intensive resource use, and environmental harmony” in agricultural systems. In China, high-standard farmland construction (HSFC) is deemed critical for promoting sustainable farmland utilization. However, its specific impact on the ecosystem service value (ESV) of farmland is still unclear. Using panel data from 31 provinces (including municipalities and autonomous regions) in China from 2005 to 2022, this study applies a continuous difference-in-differences (DID) model to assess the effects of HSFC on farmland ESV and its underlying mechanisms. The findings indicate that HSFC significantly enhances the ESV of farmland. This positive effect is robust across various tests, such as replacing core explanatory variables, adjusting for policy interference, and using control variables lagged by one period. The policy improves the ESV of farmland by advancing agricultural modernization and facilitating production concentration. Heterogeneity analysis shows that the impact of HSFC on farmland ecosystem services is more evident in provinces within the lower value quartiles compared to higher quartiles. Additionally, the effect is more pronounced in major grain-producing areas than in non-major grain-producing regions, and is stronger in the eastern and western regions than in the central region. It is recommended to enhance the widespread and effective implementation of the HSFC policy while encouraging agricultural technological progress, developing appropriately scaled operations, and crafting differentiated HSFC policies. </p>