Abstract: An artificial rainfall and simulated overland flow test was conducted to study runoff and sediment yield process and hydraulic characteristics of uncovered earth road and grass-covered earth road in order to decrease soil and water loss on grass-covered earth road surface. Total runoff and sediment yield decreased 3.94%-25.10% and 9.65%-45.69% respectively of grass-covered earth road compared with uncovered earth road. At same flow rate, grass-covered earth road had lower soil erosion rate, runoff velocity and unit energy of water-carry section. Darcy-weisbach resistance coefficient and Manning roughness coefficient of grass-covered earth road was 2.62-9.00 times higher and 1.74-3.53 times higher respectively than that of uncovered earth road. Because of its lower runoff velocity and unit energy of water-carrying section, higher road surface roughness coefficient and runoff resistance coefficient, grass-covered earth road had a lower sediment yield and could decreased sediment transport. The study provides theoretical support for decreasing uncovered earth road erosion and paving grass-covered earth road.