Abstract: The ecological risk of the sediments of the Wuliangshuhai Lake was studied with the Hakanson potential risk index.The results show that the potential risk index of heavy metals in the sediment decreases as follows: Hg>Cd>As>Cu>Pb>Cr>Zn.Hg and Cd are the most hazardous elements.Ecological risks are different in different region:the western and northern areas are bigger than the eastern and southern areas.This is related to natural factors and human activities.The sediments of the Wuliangshuhai Lake should be used carefully as farmland fertilizer due to the contamination risk of heavy metals.