To investigate the impact of the Grain for Green Project on water storage in the Loess Plateau region, we utilized Gravity Recovery and Climate Experiment gravity data to invert the spatiotemporal changes in water storage from 2006 to 2020 and analyzed the dynamic effects of the Grain for Green Project on water storage in conjunction with the Leaf Area Index. The results indicate that: (1) the trend of terrestrial water storage change from 2006 to 2020 is -0.60 +/- 0.06 cm/year; after deducting the influence of coal mining, the trend is -0.40 +/- 0.06 cm/year, spatially, it consumption increases gradually from west to east; (2) the area where Leaf Area Index remarkably increases is generally consistent with the region where cropland has been converted to forest, indicating that the Grain for Green Project has achieved certain effects in improving vegetation coverage; (3) groundwater witnessed a decrease, while evapotranspiration increased from 2006 to 2010. During the pause in project activities, the downward trend of groundwater has slowed down. Following the commencement of the new round of afforestation in 2014, groundwater saw a significant decrease once again, while evapotranspiration continued to rise more markedly. These results affirm that enhanced vegetation cover due to the Grain for Green Project may lead to increased groundwater consumption. This study reveals the significant impact of the Grain for Green Project to the water resources of the Loess Plateau, providing guidance for vegetation restoration and water resource management in arid and semi-arid regions.