研究古湖泊是开发水资源的有效途径。山西省中部的太原盆地在早更新世时是一片汪洋大泽，进入历史时期湖水南泄，在介休以北，平遥、祁县、太谷以西，文水、汾阳以东形成一个残留的湖泊，即昭余祁，《尔雅·释地》将该湖列为全国十薮之一。此后昭余祁有两次大的淤缩，第一次是汉代，第二次是唐宋时期，元代以后成了面积较小的昭余池和芦苇之地。利用遥感卫片根据比值合成影象进行解译，发现在昭余祁的范围内有3个完整的、大小不同的闭合结构图斑，分别为3个时期的变化范围。再通过地层岩性资料和实地考察来分析，其结果与史籍和遥感解译相同。最后说明了昭余祁湮塞的原因。

Researches into ancient lakes help using water resources effectively. Taiyuan, which lies in the middle of Shanxi province, had been a vast expanse of water in the pre pleistocene epoch. In the early stage of history, the water began to flow southward, and a remaining lake Zhao Yu Qi was formed in the north of Jiexiu, the west of Pingyao, Qixian and Taigu, and the east of Wenshui and Fenyang. In the pre Qin days, the lake was among the ten largest lakes in the country. Afterwards, Lake Zhao Yu Qi experienced two severe shrinkages; one happened during Han Dynasty; another happened from Tang Dynasty to Song Dynasty. Since Yuan Dynasty, the lake gradually came to be a pond and reed marshes. According to remote sensing satellite photos and images, it is found that there are three integrate spots in closed structure that are different in size. They are proved to be the changing ranges in three periods respectively. Furthermore, the stratigraphic lithology and on the spot investigatings also confirm what the historical records and remote sensing technology have shown. At the end of the paper the reasons why the Lake Zhao Yu Qi was silted up are given.