Abstract: The Widely seepage of surface water will bring about the rise of ground level in loess area, reducingthe collapsibility of loess and increasing the compressibility of loess, foundation soils wills changing to worse.Thus the wide range of saturated soft soil will be occured and formed unfavorable engineering conditions by man-made. The paper takes the seepage of Xingqing fake in Xi'an for example and discusses the unfavorable building foundation conditions of saturated soft loess around the lake to give some cautions.