Objective Channels are key areas where soil erosion occurs and develops. However, their morphological differentiation characteristics across different scales remain unclear. This study aims to investigate the characteristics and spatial differentiation patterns of channel morphological parameters at both small-watershed and micro-watershed scales.

Methods This study was conducted in a small watershed in the northern foothills of the Dabie Mountains, based on multi-source data including 5 m DEM, 2 m high-resolution imagery, and field surveys. Through integrated application of GIS-based hydrological analysis, ROC curve–Youden’s index method, and spatial statistics, the characteristics of channel morphological parameters and their spatial differentiation patterns at both small-watershed and micro-watershed scales were investigated.

Results 1) The optimal flow accumulation threshold for channel extraction in the study area was 1.26 hm². A total of 227 channels were extracted, with an overall accuracy of 87.22%. The RMSE of channel heads was 24.69 m, the cosine similarity was 0.999 5, and the channel overlap deviation was 1.83%, indicating good extraction performance. 2) At the small-watershed scale, the number of channels decreased sharply with increasing channel level, dominated by first-level channels (80.62%), with a mean elevation difference of 6.89 m. Channel level showed a significant positive correlation with channel length (r = 0.683, P < 0.01) and significant negative correlations with gradient (r = −0.358, P < 0.01) and relief (r = −0.384, P < 0.01). 3) Channel densities ranged from 1.71 to 27.02 km/km² at the micro-watershed scale. The maximum channel level showed a significant negative correlation with gradient (r = −0.567, P < 0.01) and a significant positive correlation with channel density (r = 0.340, P < 0.01). Spatially, the maximum channel level, mean gradient, and mean relief exhibited significant positive spatial autocorrelation (Moran’s I ≥ 0.135, P < 0.01), while channel density showed a random spatial distribution.

Conclusions The coupling relationships between channel morphological parameters and topographic factors in the small watershed of the hilly region of the northern Dabie Mountains are scale-dependent. The findings of this study can provide supporting data for accurate channel identification and soil erosion prevention and control in this region.