Abstract: Hippophae rhamnoides Linn afforestation has been used as a major water and soil conservation measure in soft sandstone area from experiment on spot to promotion in large scale more than 40 years.The project of Hippophae rhamnoides Linn afforestation in Shanxi,Shaanxi and Inner Mongolia soft sandstone area that has been implemented since 1998,has made sea buckthorn afforestation area increased to a new level.Through the implementation of the project,the environment and vegetation cover have been greatly improved;soil erosion amount reduces year by year.In order to evaluate the reduction effects of flood and sediment yield by Hippophae rhamnoides Linn forest.Based on soil conservation method,the effects of flood and sediment yield reduction were calculated,and the role of sediment reduction to the tributaries that directly flow into the Yellow River was analyzed.The result showed that the area proportion of sea buckthorn forest accounts for the total forest in the watershed of the project area increased year by year,flood and sediment yield reduction has also increased yearly.In the years 2002—2008,the average annual total flood and sediment yield reduction of Huangpu river,Gushan river,Kuye river,that reduced by Hippophae rhamnoides Linn forest is 4 808 400 m3and 3 026 500 t respectively.The results has an important role in guiding the configuration of soil and water conservation measures in soft sandstone area.