Based on panel data from 11 provinces in the Yangtze River Economic Belt from 2012 to 2021, the impact and mechanism of financial support for agriculture on farmers' income was empirically analyzed using spatial econometric models. It is found that financial support for agriculture has a significant promoting effect on farmers' income through the accumulation of rural human capital, and there is a significant positive spatial spillover effect. Relevant policy recommendations are proposed to expand the scale of fiscal support for agriculture, accelerate the formulation of policy measures based on spatial spillover effects, and improve the efficiency of the use of fiscal support for agriculture funds.