Abstract: The tensile strength of the vertical geotextile belts (the extended roots) can play a longer mechanical reinforcement than the plant roots, but it will also have an impact on the depth of rainfall, further change the hydrological response of slopes. The hydraulic characteristics of clay slopes reinforced by vegetation and vertical geotextile belts are calculated, and the comparison between bare clay slope and vegetated slope is made. The results show that the vertical geotextile belts play a good role in transferring rainwater to deep slope soils during rainfall and moisture from deep to shallow slope soils during drying. After 10 days of rainfall, the rainfall infiltration depths of the bare clay slope, the vegetated slope and the slope reinforced by vegetation and vertical geotextile belts (the vegetation reinforcement layer is 20 cm thick and the vertical geotextile belt is 50 cm long) are 0.6 m, 0.9 m and 1.2 m, respectively. After drying process for 14 days, the moisture contents of soils in the surface layer of slopes are as follows: the slope reinforced by vegetation and vertical geotextile belts > the vegetated slope > the bare clay slope. In addition, the design parameters such as length and spacing of the vertical geotextile belts will affect the rainfall infiltration depth of slope soils and rainfall distribution on slope surface. The longer the vertical geotextile belts, the deeper the rainfall influence depth; the smaller the spacing of vertical geotextile belts, the smaller the slope runoff, and the less the water accumulation at the toe of slopes. Planting thin and dense vertical geotextile belts can improve the water accumulation at the toe of slopes, restrain the development of surface cracks, and reduce the risk of landslides under rainfall.