The Yellow River Basin, a critical ecological barrier and economic zone in China, has experienced significant changes in vegetation cover and aerosol concentrations in recent decades, driven by large-scale ecological restoration projects and air pollution control policies. These changes exert profound and interconnected influences on regional climate and hydrological cycles. This review synthesizes current understanding of the individual and co-interactive climate-hydrological effects of vegetation and aerosol variations in the upper-middle Yellow River Basin. Vegetation restoration, particularly in the Loess Plateau, has led to a marked "greening" trend, characterized by increased leaf area index and vegetation coverage. This greening directly regulates surface energy and water balances. Primarily, it enhances evapotranspiration (ET) through increased transpiration and canopy interception, consuming substantial soil water and contributing to soil moisture depletion, even forming persistent dry soil layers. Vegetation restoration affects precipitation through both local moisture recycling (via increased evapotranspiration) and large-scale circulation adjustments, though quantifying its net effect remains constrained by model uncertainties and regional climate variability. A dominant hydrological consequence is a significant reduction in river runoff, attributed largely to increased ET and improved infiltration, posing challenges for water resource management. Concurrently, aerosol optical depth (AOD) in the region has shown a declining trend since 2011, despite persistent spatial heterogeneity. Dominated by sulfate and dust particles, aerosols influence the hydrological cycle through both radiative and microphysical pathways. Their direct radiative effects (scattering and absorption) alter surface temperature and atmospheric stability. Indirectly, by acting as cloud condensation or ice nuclei, they modify cloud properties-affecting microphysics, lifetimes, and precipitation efficiency-which can either suppress or enhance rainfall depending on aerosol type and meteorological conditions. These aerosol-driven modifications collectively alter precipitation patterns and surface radiation, thereby influencing potential ET. Specifically, aerosol-induced radiative cooling can reduce surface evaporative demand, while their impact on precipitation directly constrains actual ET and soil moisture recharge. Furthermore, by altering precipitation intensity and distribution, aerosols can elevate flood risk. In the Yellow River's source region, absorbing aerosols also contribute by reducing snow and ice albedo, which accelerates melting and alters the seasonal runoff distribution. Critically, vegetation and aerosols do not operate in isolation but engage in complex bi-directional interactions. Vegetation affects aerosols by emitting biogenic volatile organic compounds (BVOCs), precursors of secondary organic aerosols, and by reducing dust emissions through increased surface roughness and cover. Conversely, aerosols influence vegetation physiologically through the "diffuse radiation fertilization effect," where increased diffuse light under aerosol-laden skies can enhance canopy photosynthesis and water-use efficiency. Furthermore, aerosol-induced surface cooling may reduce soil evaporation while potentially increasing transpiration under specific conditions such as high temperatures with few clouds, creating a nuanced net effect on ET. These interactive effects extend to soil moisture and runoff, resulting from the integrated outcomes of altered precipitation, ET, and vegetation responses. In conclusion, the coupled "vegetation-aerosol-climate-hydrology" system in the upper-middle Yellow River involves multisphere, nonlinear feedbacks. Current research has outlined key individual and interactive mechanisms but leaves significant gaps in understanding. These include a lack of fully coupled modelling integrating hydrological, ecological, and atmospheric chemical processes; insufficient region-specific observational data and empirical studies; weak quantitative analysis of co-interactive effects; limited predictive capability under future climatic and anthropogenic scenarios; and inadequate understanding of nonlinear feedback processes. To address these limitations, future efforts should prioritize developing fully coupled regional Earth system models integrating hydrological, ecological, and atmospheric chemical processes, and strengthening long-term, multi-platform observational networks to better quantify these interactions and inform sustainable water-resource and ecosystem-management strategies for the basin. Furthermore, this research paradigm also provides a valuable reference for studies of land-atmosphere coupling processes in other ecologically vulnerable regions worldwide.