The Grain to Green Project (GGP), China's largest land restoration initiative, has profoundly altered land use and cover in the Loess Plateau, leading to significant enhancements in ecosystem services. This study examines the dynamics of these services and their values during and after GGP implementation, assessing the project's net economic benefits to inform future land restoration policies. We integrated observed land use changes and employed the CLUE-S model to simulate a 2020 land cover scenario without GGP implementation (2020 NoGGP) and three scenarios for 2030. Utilizing ecosystem services models, statistical data, and expert knowledge-based valuation, we quantified and monetized 10 ecosystem services for each scenario. Our findings indicate that without GGP implementation since 2000, provisioning services would have continued to increase at the expense of regulating services. Fruit production demonstrated a synergistic relationship with carbon sequestration and sediment retention but exhibited trade-offs with water yields. From 2000 to 2020, there was a marked increase in the monetary value of ecosystem services, with the 2020 NoGGP scenario showing a 57% (USD 2385 million) decrease compared to actual 2020 outcomes. For the 2030 scenarios, our cost-benefit analysis indicates that afforestation provides greater economic returns than grass planting but is associated with reduced water yield. By jointly valuing carbon sequestration, soil conservation, and other key ecosystem services over multiple decades, this study illustrates how long-term ecological restoration can contribute to global climate and land degradation targets while informing national policies on rural development and land-use planning.