Based on post-flood remote sensing images, measured cross-section data, and upstream water-sediment data from the Xiaobeiganliu reach of the Yellow River from 2000 to 2020, several characteristic parameters, including the swing width of the main channel, sinuosity coefficient, braiding coefficient, and central bar area ratio, were selected to analyze the evolution characteristics of the river regime in this reach and its main influencing factors. The results show that the swing width of the main channel gradually stabilized, with a multi-year average of 451 m, exhibiting strong variability in the upper section and relative stability in the middle and lower sections. The sinuosity coefficient ranged between 1.0 and 1.3 over the years, still reflecting the wandering nature of the channel. The braiding coefficient and central bar area ratio fluctuated markedly over time, with central bars being scattered and highly dynamic. Upstream inflow volume had a significant influence on river regime changes: both the sinuosity coefficient and braiding coefficient showed negative correlations with the inflow volume and its deviation from the multi-year average. Training works and natural control points worked together to narrow the channel, regularize the main flow, and thereby affect the river regime evolution.