Based on the data of grain yield in ten experimental areas,the situation and potential increase of grain yield in the soil loss region of Loess Plateau were studied from three different levels of yield,which are dryland yield potential,experimental yields in ten areas and yields of ten counties.The results indicated that the potential yield increase was greater in the soil loss region of Loess Plateau,and the present yield only reached 74.7% of the experimental level in ten areas,and 54.2% of the sunlight temperature water yield potential.Comparison of dryland potential yield increase in gully and hilly regions of Loess Plateau shows that potential yield increase in hilly region is 117.6%,and only 56.6%in gully region.Owing to population increase and decrease of cultivated land in the soil loss region,the produced grain yield will not meet the need in the future thirty years.