Vegetation plays a critical role in controlling gully erosion. However, few studies have clarified the effects of shrub and its components on gully bed erosion processes by altering the flow hydraulics and soil loss. In this study, a series of in situ scouring experiments were conducted to investigate the influence of shrub stem and litter on the concentrated flow pathway characteristics, hydraulic properties, and sediment yield during gully bed erosion. The experiments involved a typical shrub named Leucaena leucocephala, with five stem coverage (0 %, 0.15 %, 0.30 %, 0.60 %, and 1.20 %) and five litter amounts (0, 100, 200, 300, and 400 g m-2). Four different treatments were applied: stem and litter (SL), stem only (OS), litter only (OL), and a control bare gully bed (BG). The results showed that, compared to the bare gully bed, the various treatments significantly enhanced concentrated flow branching, increased Darcy-Weisbach friction factor (f), and reduced flow rate, velocity, shear stress, and soil loss rate. The combined effect produced by SL treatment on runoff and erosion was the strongest. Stems were most effective in reducing flow velocity and shear stress, contributing an average of 21.23 % and 7.54 %, respectively. Litter primarily increased the flow resistance f and reduced flow rate and soil loss rate, with average contributions of 123.59 %, 20.60 %, and 27.67 %, respectively. Increasing stem coverage and litter amount increased their contribution of controlling runoff and erosion. When the litter amount exceeded 200 g m-2, it gradually replaced stems as the dominant role in increasing flow resistance f and reducing concentrated flow and erosion in the both stems and litter covered gully beds. These findings enhance the understanding of how shrub and its components control gully development and highlight the importance of maintaining litter in the gully beds to mitigate gully erosion.