Abstract: High-standard farmland construction is crucial to the overall development of agricultural modernization, serving as both a "stabilizer" for food security and a “golden key” to increasing farmers’ income. Based on panel data from 31 provinces (municipalities and autonomous regions) in China from 2005 to 2023, this study employs an intensity difference-in-differences model to evaluate the impact of the high-standard farmland construction policy on farmers' income and its underlying mechanisms. The findings are as follows: 1) The high-standard farmland construction policy has a stronger promoting effect on operational income than its inhibiting effect on wage income, significantly boosting overall regional farmers' income. 2) Heterogeneity analysis reveals that the policy's impact on farmers' income exhibits uneven effects, with more pronounced income-increasing outcomes in regions characterized by low agricultural labor transfer, high agricultural disaster rates, and low rural human capital. 3) Mechanism tests indicate that the policy primarily drives regional farmers’ income growth through agricultural mechanization and large-scale agricultural operations, with synergistic effects between the two creating a self-reinforcing mechanism for income enhancement. Based on these findings, it is recommended to prioritize both the “construction” and “maintenance” of high-standard farmland, promote its development according to local conditions, focus on the two core elements of agricultural mechanization and large-scale operations.