The presence of flexible vegetation on slopes has a significant impact on the hydrodynamic properties of overland runoff, which in turn contributes greatly to slope erosion. Prior research has concentrated on the entirety of flexible vegetation, encompassing both stems and foliage. To further elucidate the impact of near-surface flexible vegetation foliage on hydraulic characteristics, simulated slope scouring experiments were conducted to study the hydrodynamic features of overland runoff under three flow rates (0.5, 1.0, and 1.5 L/min), five slope gradients (2°, 4°, 8°, 12°, and 16°), five coverage degrees, and two coverage types. This research aims to reveal the influence of near-surface coverage by flexible vegetation foliage on the erosion characteristics of slope soil. To delve into the effects of the foliage of near-surface flexible vegetation on the hydrodynamic properties, we employed simulated slope erosion tests to examine the hydrodynamics of overland runoff under seven coverage types at flow rates of 0.5, 1.0, and 1.5 L/min, so as to uncover how near-surface foliage coverage of flexible vegetation influences the erosion traits of slope soils. The findings indicate that the average flow velocity decreases with the increase of the coverage of flexible vegetation foliage, and the rise in flow rate and slope angle mitigates the reduction in average flow velocity. Both Reynolds number (Re) and Froude number (Fr) diminish as the coverage of flexible vegetation foliage expands, with a pronounced reduction in Fr and a more gradual decrease in Re. The interplay between foliage coverage and slope gradient significantly influences the flow state. The resistance coefficient increases with the increase of the foliage coverage,suggesting the coverage’s role in augmenting resistance.Variations in slope gradient result in a fluctuating resistance coefficient, which decreases first, then increases, and decreases again, with the transverse morphological resistance of various coverage types under identical conditions constituting a larger share of the total resistance. The research results can provide a technical support for the management of slope soil erosion and ecological environment in the Loess Plateau.