Three original physiognomy plots (besides bare slope , grass slope and shrubby slope) were const ructed in the Yaner watershed. The amounts of the runoff,erosion and seeping rate in different sections in two years were analyzed. The data were found to vary with different rainfall events. Under the same condition , the amount of runoff on bare slope was 6 times greater than that on grass slope , and 2. 4 times greater than shrubby slope,which indicated that bare slope produced more runoff than other two. The amount of erosion on bare slope was 82 times greater than that on shrubby slope , and 150 times greater than that on shrubby slope. This suggest s that grass and shrubby can greatly reduce soil erosion in the Loess Plateau. Seeping rate varies with all the rainfall event s. Gener2 ally speaking , seeping rate on shrubby slope is 90%,grass slope,85%,and bare slope,60%.It is a comparative advantage in melioration of the Loess Plateau to grow grass or shrub.