The river network structure in the Middle Yellow River basin has various macroscale geometrical patterns.The morphological parameters of river networks were obtained using the TOPAZ software,using DEM data analyzed with appropriate extraction parameters.Statistical analyses of the geometric structures and topological morphology of the river networks showed that the Horton-Strahler and Tokunaga laws hold well within a certain range of scales,demonstrating self-similarity in the structure.Furthermore,the parameters characterizing this self-similar pattern have stable values showing negligible change over a given range of scales,which suggests their independence in regard to the macroscale geometrical patterns of the river networks and the regions where they are located.