Baseflow is the main contributor to river discharge during droughts and is essential for maintaining watershed water security. The Loess Plateau (LP), located in northern China, is an ecologically fragile region that has undergone large-scale land surface changes since the implementation of the "Grain for Green" Program (GGP) in 1999. The effects of vegetation restoration under the program on baseflow stability, especially under hydrological drought or low-flow conditions, are still insufficiently understood. In this study, six representative catchments on the LP, including the Kuye, Qiushui, Dali, Xinshui, Yan, and Malian Rivers, were selected for analysis. Daily streamflow records (1950 s-2021) and annual land use data (1990-2022) were analyzed. Eight baseflow separation methods were evaluated and compared. Trend analysis, elasticity coefficient estimation and coefficient of variation were used to assess the stability of hydrological variables: to examine how land use changes influence baseflow stability during hydrological droughts and to quantify the regulating role of vegetation restoration. The main findings were as follows: (1) The PART separation method performed best in the study region, with both NSE and KGE values exceeding 0.90. (2) During the study period, streamflow in the typical catchments showed a significant downward trend (p < 0.05), while the baseflow index (BFI) increased significantly (p < 0.05), whereas baseflow showed no significant trend in most catchments. (3) Compared with non-drought periods, the mean streamflow and baseflow during drought periods decreased by 36.85%-92.21% and 17.44%-88.94%, respectively, while the mean BFI increased by 4.97%-90.58%. (4) Since 2000, the inter-annual variability of streamflow, baseflow, and BFI has decreased, indicating greater hydrological stability. Forests and grasslands exerted stronger regulation on baseflow stability than other land use types, particularly during hydrological droughts. These findings provide a scientific basis for optimizing water resource management and evaluating the ecological benefits of vegetation restoration on the LP, providing methodological insights for ecohydrological studies in semi-arid regions influenced by land surface changes.