To study the structural characteristics of the river network in the Jinsha River Basin, river networks were extracted based on ASTER GDEMV3 data and the river network density method. By using the Horton-Stahler hierarchical method combined with indicators such as box dimension, bifurcation ratio, length ratio, and side-branch ratio, the self-similarity patterns and structural features of the Jinsha River Basin were analyzed, as well as the morphological characteristics of the main stream. The results indicate that rivers of levels 1-6 in the Jinsha River Basin exhibit structural and topological self-similarity, whereas rivers of levels 7-8 show no significant self-similarity. At the basin scale, box dimension and river network density satisfy self-similarity, with upper reaches characterized by smaller box dimensions and higher river network density, while the opposite is observed in the lower reaches. Topographic factors play a more dominant role than climatic factors in influencing box dimension and river network density in high-mountain canyon-type basins in southwestern China, such as the Jinsha River Basin. The river networks in high-altitude plateau regions generally exhibit higher bifurcation and length ratios but lower side-branch ratios. The upper reaches of the main stream of the Jinsha River feature gentle slopes and larger meander radii; the middle reaches have steep slopes and relatively straight channels, and the lower reaches show gentle slopes and smaller meander radii. As the length of the studied river segments increases, the average sinuosity, the range of sinuosity, and data dispersion all increase accordingly. Overall, an inverse relationship exists between river segment sinuosity and channel gradient.