临夏盆地东山古湖（２．３５～１．６５ＭａＢ．Ｐ．）沉积厚达８４ｍ，是六盘山以西早更新世湖相沉积的典型代表。以２．５ｍ的间隔对其进行系统采样，以ＣａＣＯ３含量变化为指标建立高分辨率的气候变化曲线，对曲线进行周期分析表明，东山古湖所反映的气候波动具有明显的４１０００ａ主导周期；其中２．２８ＭａＢ．Ｐ．和１．７５～１．８０ＭａＢ．Ｐ．时段为两个明显的冷湿时期，表明东亚季风在建立初期具有不稳定性。 The ancient sediment of Dongshan Lake (2.35 ~ 1.65MaB.P.) In Linxia Basin is 84m thick, which is typical of the Early Pleistocene lacustrine deposits west of Liupanshan. The samples were sampled systematically at intervals of 2.5m, and high-resolution climatic change curves were established with the change of CaCO3 content. The periodic analysis of the curves showed that the climate fluctuations reflected by the ancient Dongshan Lake had obvious dominant cycles of 41000a. 2.28MaB. P. And 1.75 ~ 1.80MaB. P. The periods are two distinct periods of cold and wet, indicating that the East Asian monsoon was unstable at the initial stage of establishment.