| Gahai Lake is a closed inland lake, which is located in the northeast Delingha Basin, Qinghai—Tibet Plateau. It is very sensitive in the response to climate change and is the ideal location to study the regional environment response to global change. Based on comprehensive analysis of granularity, magnetic susceptibility (average resolution is 37a) and pollen (average resolution is 65a ) in DG02 core obtained from the west-northern margin of Gahai Lake, and compared with the climate records from the adjacent areas, this article reconstructed the Holocene climate and discussed the possible climate change-driven mechanism in the study area.Gahai Lake had gone through three major paleclimate stage in the Holocene. The first stage was from 11400 to 7910cal aB.P., which was corresponding to early Holocene. The climate was cold and wet, which can be divided into two periods. The early period was at the end of the Younger Dryas cold event, with inceasing temperature and precipitation. In the late period the temperature decreased slightly but the precipitation is still high, which means the climate was relative wet and cold. The second stage was from 7910 to 5110cal aB.P., with the climate of warm and wet, and the combinations of the heat and precipitation in this region were best of all epoch, which was actually the Holocene optimum. The third stage was from 5110 to 230cal aB.P., with the climate of cold and dry as a whole, which can be divided into three periods. In the early period, the climate was cold and wet. In the second period, the temperature recovered slightly and the climate was warm and dry. Later, the climate was cold and wet. At the same time, it had six cold or dry events in 8.2cal kaB.P., 6.4cal kaB.P., 5.8cal kaB.P., 5.2cal kaBP, 2.6cal kaB.P. and 1.2 cal kaB.P. in the Holocene.Climate change in the Gahai Lake since Holocene was similar to the record of marginal zone of monsoon, but there were some differences of details in the climate change, due to different sensitivity of climate proxy and the regional climate. Taking into account the different precision of climate proxy, dating precision et al, the affirmation of some key Holocene climate events would depend on more accurate data of chronology and samples.Based on the Coexistence Approach that reconstructed Holocene climate, the result showed the coexistence intervals of each parameter: mean annual temperature(2.2～8℃), mean annual precipitation(131～363mm), mean temperature of the coldest month(-15.8～-8℃), mean temperature of the warmest month(18.5～23℃), mean minimum monthly precipitation(2～3m), mean maximum monthly precipitation (26.4～88.4mm), growing-day degrees above 5℃(1578～2458℃·d), mean relative humidity(49～57%). The Holocene climate overall consisted with modern climate types in Gahai Lake, but it had small fluctuations at different periods. The highest annual average temperature reached the highest in Mid-Holocene(7910～5110 cal aB.P.), but it began cold at 5110cal aB.P. and gradually become a modern temperature. Precipitation in Holocene was more than modern time's. Precipitation was the most in early Holocene(11400～7910cal aB.P.) and then the precipitation gradually deceased and then emerged drought in the late Holocene(5110～230cal aB.P.).Gahai Lake, which is located in the monsoon marginal, may be influenced by westerly circulation and the Asian summer monsoon at different stage in the Holocene, and also contacts with the low latitude air–sea interactions of the tropical ocean regions.
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