Huangqihai Lake is an inland closed lake. Climatic change is a major factor to control the lake level fluctuatiunc. The analysis on geomorphology, lacustrine sedimentolugy, geuchemistry and historical archecnugy proves that the lake level has been fluctuating since 10000 a B. P. During the early Holocene, the lake level began rising and reached its maximum height at y000a B. P. ur a maximum area of the lake. Then the lake level began to fall and its surface area to be reduced successively.