In recent years, the increasing attention has been paid to the emission management of pollutants from non‑road mobile machinery in China. Based on the background of non‑road mobile machinery emission policy from National Ⅲstandard to National Ⅳ standard, the environmental value and economic cost of emission reduction for large, medium and small agricultural tractors are studied in this paper. At the national provincial level, the cost‑benefit analysis method is adopted to evaluate this policy quantitatively, and further conduct the simulation analysis and sensitivity analysis of emission reduction scenarios.The study found that within the research time period (December 1, 2022, to November 1, 2023), an environmental benefit of approximately 5.48 million tons of emission reduction was created in the whole country, with Henan Province achieving the highest benefit of 760 000 tons. In terms of average benefits per unit, the national average environmental benefit per tractor under National Ⅳ was 51 yuan. However, achieving this volume of environmental benefits requires an economic cost of approximately 1 191 yuan per tractor, which is approximately 23 times of the average environmental benefit per tractor. By 2030, under a comprehensive scenario, the emission reductions of CO, HC, NOX, and PM particles will increase by 54.32%, 42.25%, 40.25% and 46.44%, respectively. Before the country updates the fifth round of emission standards for non‑road mobile machinery, increasing the utilization rate of tractors under the National Ⅳis the most effective way to balance emission reduction, economic cost, and environmental benefits. Technological upgrades and cost reductions are the most favorable methods to optimize the policy income‑cost ratio.