Lake Qinghai is the largest one in China, which is located in the semiarid region of Tibet-Qinghai plateau with an enclosed drainage basin. In early middle Holocene (about 6000~7200 a. B. P.), there was a high lake level approximately 45m above present. The research on the palynology around the lake exposed the climatic characteristics from vegetation coverage is wetter and warmer than that of present, namely the atmospheric temperature is about 4℃ over modernday. By the aid of various information supplied by palynology, sedimentary, morphology and chronology, we try to establish the paleolake water budget. The conclusion has been reached that the precipitation,evaporation and runoff in paleolake region is 32.0%, 14.0% and 67.0% larger than the present respectively.