The heavy metal content in the sediment of Wangjiaya Reservoir in Baoji City were determined by using X-ray fluorescence spectrometry and their ecological risk were assessed by using the potential ecological risk index.The results indicate that the average contents of As,Co,Cr,Cu,Ni,Mn,Pb,V and Zn in the sediment were higher than the soil background values of Shaanxi Province.The accumulation coefficient of Cu was the highest among the studied heavy metals,while Zn was the lowest.The heavy metal element distribution in the sediment had the similar horizontal character,which was high content in the reservoir centre,low values in the reservoir up-reach.The results of potential ecological risk assessment showed that the ecological risk degree of the heavy metal pollutants was moderate,and the highest comprehensive ecological risk was in section 5(in the middle reach) and lowest was in section 8(in the upper reach).The order of individual potential ecological risk was AsCuNiCoPbVMnCrZn.As had the moderate ecological harm and other heavy metals have lower ecological risk.