北京延庆盆地是一个小型的新生代断陷盆地，第四纪时期曾发育多期湖相层，而对这些湖相层的时代有着不同的认识。应用电子自旋共振（ＥＳＲ）测年方法对采自北京延庆盆地地表湖相沉积层的６个钙质样品作了年龄测定，结果表明，延庆盆地地表出露的较老湖相层的时代属于中更新世。 The Yanqing Basin in Beijing is a small Cenozoic rift basin. The Quaternary period developed multi-stage lacustrine facies, and had different understanding of the age of these lake facies. The age determination of six calcareous samples collected from the surface lacustrine sediments in Yanqing Basin, Beijing by ESR dating shows that the age of the older lacustrine layers exposed in the surface of the Yanqing Basin belongs to Middle Pleistocene.