Soil erosion and sediment outflow processes are complex and dynamic in nature and depend on several factors such as climate, topography, soil, and management conditions. In bio-engineering projects, plant species are used to control surface erosion and improve the stability of slope. With hydrologic point of view, plants reduce soil erosion as they help in intercepting rainfall, reducing the kinetic energy of raindrop, enhancing infiltration, reducing the velocity of flowing water by providing the roughness over the land surface, transpiring soil water and adding organic matter to the soil and improve soil structure. An experiments were performed in a hydraulic tilting flume and controlled water circulation system. An experiments were carried out using three treatments 1. Control 2. Whole plant plot and 3. Roots plot at 1%, 2% and 3% slope with 6.6 l/s/m, 9.0 l/s/m, 10.7 l/s/m and 12.4 l/s/m runoff rate. Results summarized that Napier grass plot significantly reduced soil erosion as compared to the control plot. Further, it was also observed that the sediment outflow generation significantly decreased with the growth stage. Roots were more effective in controlling sediment rates compared to shoots.