Ecological cropland conversion is the process of transforming unsuitable farmland back to forests, grasslands, water bodies, or wetlands for the purpose of ecological restoration. However, a comprehensive analysis of the effectiveness and drivers behind these endeavors remains lacking, especially in transitional zones where agricultural production and ecological protection must be balanced. This study identified the effectiveness of ecological cropland conversion in the Agro-pastoral Ecotone of Northern China (APENC), focusing on ecological land protection, land structure transformation, and contributions to ecosystem services. The Geodetector model was used to analyze the potential driving factors behind these efforts. The results indicate that: (1) From 2000 to 2020, APENC converted approximately 4,578,363.54 ha of non-ecological land into ecological land, with cropland conversion accounting for 91.5 % of the area. (2) Cropland-to-grassland conversion measures demonstrate substantial short-term advantages, accounting for 94.0 % of the total ecological cropland conversion area. (3) During 2000-2020, APENC's ecological cropland conversion increased ecosystem service value by 57.4 billion Chinese Yuan (CNY), with 65.5 % of this increase derived from ecosystem regulation services. (4) Regarding driving forces, human factors, including population, agricultural activities and infrastructure, are crucial in determining the effectiveness of these efforts. However, it is essential to emphasize that the interaction between natural factors and socio-economic and policy-related influences offers a more comprehensive explanation for the spatial variations seen in ecological restoration outcomes. APENC should balance food production and ecological protection, integrating ecological restoration with agricultural development trends, while also systematically advancing the construction of regional ecological protection compensation mechanisms.