Based on preceding investigation, themonitored sample numbers on the slope of Shaanxi section on Xi'an-Nanjing railway are calculated under given reliability. Under 90% reliability and 92% estimation precision,the mean vegetation coverage and its error value is 15.81% and 1.2%, respectively.The mean soil erosion intensity and its error value are 1715.14 t/km² and 162.595 t/km² respectively under 90% reliability and 90. 52% estimation precision.