The potential effects of sediment load (S) on hydrodynamic parameters of overland flow were investigated in a smooth plexi-glass flume under a wider range of sediment load and slope gradient of 9°. The results showed that Reynolds number (Re) decreased as sediment load increased, implying a decrease in flow turbulence. Froude number, mean flow velocity and correction factor to flow velocity (α) first all decreased with sediment load increasing and then the values all suddenly increased and gradually become stable as sediment load further increased when S>300kg/m3. The mean α was 0.554. For the difference between standard of energy dissipation in sediment-laden and clear-water overland flow, the conclusions were also different. When S<300kg/m3, the friction coefficient of sediment-laden flow was larger than that of clear water flow either with the same Reynolds number or unit flow rate as standard. While, when S>300kg/m3, the friction coefficient of sediment-laden flow was smaller than that of clear water flow with the same Reynolds number and larger with the same unit flow rate.