Soil and water loss is now a major environmental problem in the Dabie mountain area of Anhui Province,which results in ecological and environmental degradation,and is harmful to local people's life and production.Based on the long-term hydrologic records of the Dasha River,authors analysed the human effects on the hydrological regimes in different times since 1970.Results show that human activities significantly reduce flood and sediment discharge and increase runoff in a dry season.The average contributive ratio affecting soil erosion by human activities is 65.6%,and at the same period the contributive ratio by runoff and rainfall is 34.4%.So,it is necessary to adopt the biological and engineering measures to solve soil and water loss problems in the Dasha River.