Ecologically fragile regions face heightened challenges in balancing ecosystem restoration with human well-beings. While ecological restoration projects like China's Grain for Green Program (GFGP) significantly alter land use and livelihoods, the pathways through which ecosystem services (ESs) affect multidimensional human well-beings, especially across diverse smallholder livelihood types, remain poorly quantified. This study developed an integrated framework combining participatory rural appraisal (PRA) and structural equation modeling (SEM) to quantify the influences of ESs (provisioning, supporting, regulating, and cultural services) on human well-beings (economic well-being, social welfare, and health security) of farmers with different livelihoods (pure rural households, part-time rural households, and non-agricultural households) in the Loess Plateau, a typical GFGP implementation area. Key findings reveal that although part-time rural and non-agricultural households have higher incomes compared to pure farmers, their overall economic well-being remains low, indicating that ESs consumption alone cannot meet the economic needs of farmers. ESs exhibit divergent effects on human well-beings. Provisioning and cultural services directly reduced economic well-being, with path coefficient (beta) of -0.417 and -0.273, respectively, while supporting (beta = 0.312 and 0.204) and regulating (beta = 0.221 and 0.188) services enhanced social welfare and health security. Interestingly, the negative impacts of ESs on human well-being were mitigated, and transmission pathways were reshaped by the livelihood mode as a critical mediator. This study offers a new perspective for understanding of the ESs and human well-being nexus, offering practical insights for enhancing sustainability policies that account for household diversity and socio-ecological complexity in ecological restoration areas.