The Yellow River is important water source in Northwest and North China.It is of great significance to understand the characteristics and causes of its streamflow changes.In this paper,impacts of climate changes and human activities such as cropland changes and water reservoirs on streamflow variations at seasonal scale were thoroughly quantified using daily streamflow data,daily precipitation data,cropland data,and information of water reservoirs in the Yellow River Basin.Firstly,multi-year trends of streamflow and change points at seasonal scale during 1960-2005 were evaluated,and then the streamflow changes during the growth period of wheat and growth period of maize and soybean were estimated by Generalized Additive Models for Location,Scale and Shape (GAMLSS) model.Besides,two different precipitation scenarios were proposed to elucidate the impacts of changes in precipitation and cropland at seasonal scale on different streamflow components defined by different percentiles.The results indicated that: 1) The change points of streamflow during the growth period of wheat and growth period of maize and soybean at the five hydrological stations in the Yellow River Basin occurred during the mid- and late-1980s and early 1990s.Except at Huayuankou Station,the streamflow in the Yellow River Basin was generally in decreasing tendency and the decreasing tendency at most hydrological stations was significant at 95% confidence level.2) Based on two precipitation scenarios set in this study,the streamflow during years with high precipitation was always higher than that during years with low precipitation,implying that precipitation still plays the critical role in streamflow changes.The impacts of cropland changes on streamflow were related with both changes in precipitation and the percentiles of streamflow components.At Tangnaihai Station,the increasing cropland increased the lower quantile of streamflow and decreased the upper quantile of streamflow during the growth period of wheat of high precipitation years while did the opposite during the growth period of wheat of low precipitation years.Results of this study can provide theoretical and practical grounds for water resources management and allocation across the Yellow River Basin.