Based on the river networks extracted from digital elevation models (DEMs) at 30 m resolution, combined with the remote sensing data, the hierarchical rules of the structural and morphological characteristics of the 6th–7th order river networks in the middle and upper Yellow River basin were analyzed. The results show that the river networks of the middle and upper Yellow River sub-basins present significant self-similar characteristics in the range of 1–5 orders. The middle reaches of the Yellow River sub-basins have higher bifurcation ratio (R_B=4.83), river width ratio (R_W=2.13) and average river length (L=4.80 km), while the upper reaches of the Yellow River basin have higher density (D=1.25 km⁻¹). In terms of river network structure, aridity index, soil water content and vegetation coverage are the main factors affecting the river network structure in the middle of the Yellow River sub-basins, while the river network structure in the upper reaches of the Yellow River sub-basins are more related to the average slope of the basin and soil erodibility. Further analysis of four typical sub-basins in the middle reaches of the Yellow River basin shows that although the typical sub-basins in the loess region have relatively higher sediment production capacity, their sediment transport capacities may be affected by the river network structure and channel morphology. This study reveals the role of river network structure and channel morphology as indicators of water and sediment transport characteristics, and emphasizes the necessity of differentiated river management measures for basins in the Yellow River basin with different underlying surface characteristics.

middle and upper reaches of the Yellow River, river network hierarchy, structure and morphology; underlying surface, basin factors, water-sediment effect