Based on comparative analysis on spatial temporal distribution characteristics of soil nutrients of typical dam land in Beigou small watershed of Yan. an City. The results showed that imbalance of soil nutrients was very serious in experimental area, and most soil nut rients were very poor, especially, soil organic matter, total Pand available P, but total K and available K were rich. The insignificant spatial and temporal differences in the soil organic matter, total N and total P were found, yet available nutrients were high-low-high from upper to lower and spatial temporal differences were significant on profile.In the light of these results, the theoretical evidences for balancing fertility of dam land are put forward.