This study focuses on typical 5th-order sub-basins within the Yellow River Basin, integrating climatic, underlying surface, and streamflow data to examine how river network structure affects the hierarchical characteristics of streamflow. Based on Horton’s laws, this study reveals that the streamflow ratio (R_Q) exhibits statistically significant self-similarity within stream levels 1–3 in the 5th-order sub-basins, consistent with the self-similar ranges of structural parameters such as bifurcation ratio (R_B), length ratio (R_L), and area ratio (R_A). Among these, R_A serves as a key reference template for streamflow hierarchy, with 75% of the sub-basins showing an  ratio between 0.95 and 1.05. Additionally, 65% of the sub-basins have  values below 1, indicating that under semi-arid climatic conditions, the growth of streamflow with stream order is generally slower than the areal expansion rate of contributing sub-basins. Further analysis demonstrates significant positive correlations (R > 0.5, p < 0.05) between  and precipitation, aridity index, and soil moisture, suggesting that sub-basins with higher rainfall and more substantial groundwater recharge exhibit a more pronounced increase in streamflow with stream order and drainage area. These findings highlight the synergistic influence of river network structure and basin characteristics on streamflow hierarchy, offering insights for water resource management in basins with diverse river network morphologies.