To determine the characteristics and influence factors of soil erosion on spoil area induced during road construction,a natural rainfall experiment was conducted along the Pingan County to A'dai town of Hualong County road,Qinghai Province during raining season.Results show that the amount of soil erosion in spoil area is significantly correlated to the amount of rainfall and its intensity.Most of soil erosion occurs in July,August,and September.The change in slope degree greatly affects soil erosion when slope degree is about 40°.Soil erosion massively increases with increased slope degree.In initial period of vegetation growth,cultivated soil is eroded more easily than dumped red soil.