Abstract: Agricultural mechanization is the only way to achieve agricultural modernization, and improving agricultural eco-efficiency is an inevitable requirement for promoting the construction of rural ecological civilization, exploring the relationship between agricultural mechanization and agricultural eco-efficiency in depth has important practical significance. This article first analyzes the relationship between agricultural mechanization and agricultural eco-efficiency from a theoretical perspective. Then based on panel data at the provincial level in China from 2005 to 2021, the global reference unexpected output Slack-Based Measure model is used to calculate the agricultural eco-efficiency of each region. Finally, an econometric model is constructed to empirical testing the impact of agricultural mechanization on agricultural eco-efficiency. The research results indicate that: The improvement of agricultural mechanization can have a significant positive impact on agricultural eco-efficiency, the agricultural mechanization mainly promotes the improvement of agricultural eco-efficiency by increasing grain income and the growth of agricultural productive service industry; The agricultural mechanization has a non-linear impact on agricultural eco-efficiency, with the increase of agricultural land transfer rate, the impact of agricultural mechanization on agricultural ecological efficiency gradually changes from negative to positive; The impact of agricultural mechanization on agricultural eco-efficiency varies significantly due to differences in terrain and landform conditions, production area positioning characteristics, degree of agricultural mechanization, and level of agricultural ecological efficiency. The research results of this article provide theoretical support and policy basis for promoting the development of agricultural mechanization and improving agricultural eco-efficiency.