The Qaidam Basin on the northeastern part of the Tibetan Plateau provides a good opportunity for investigating the relationships between tectonic uplift, climate change and continental chemical weathering, due to the unique location and continuous deposits. A Sino-German research team has carried out a joint scientific drilling program in the depocenter of the Chahansilatu subbasin (38°24'35.3"N, 92°30'32.6"E) in the western Qaidam Basin. The deep drilling core (SG-1) (938.5 m in depth) is characterized by high-quality continuous fine-grained lacustrine sediments with an average recovery of ca. 95%. Combined with previously reported acetic acid-dissolved manganese (Mn) records this study uses the new 722 evaporite sulfate and potassium ions data, and 239 chemical alternation index (CIA) and 20 Nd isotopes data in acid-residues of the SG-1 core sediments, to reconstruct the regional catchment climate change, silicate chemical weathering, and to explore further their influence factors during the Quaternary period. epsilon_(Nd) values in acid-residues vary between -9 and -10.5, show a stable secular trend, suggesting a nearly stable provenance in the paleo-lake catchment. The CIA values in acid-residues range from 54 to 72 with a mean of 65, indicating a moderate-weak catchment silicate weathering intensity. The CIA record exhibits a long-term decrease trend with a short low stage between 2.2 ~ 2.0 Ma, and two accelerating shifts at ca. 1.2 Ma and 0.6 ~ 0.5 Ma. The CIA variation is quite similar with those of sulfate ion and acetic acid-Mn as well as the reconstructed lake level change, collectively suggesting a coupled long-term evolution between the catchment and lake. The catchment-lake system displays long-term catchment climatic aridification, weakened silicate weathering, lake salinity increase and lake level decline,with a short enhancement period between 2.2~2.0 Ma and two obvious stepwise enhancement stages starting at ca. 1.2 Ma and ca. 0.6~0.5 Ma, respectively. On a longer timescale (> 105 years), the reconstructed climate change and silicate weathering intensity in the western Qaidam Basin can correlate well with North Atlantic Ocean sea surface temperature, suggesting that global cooling, especially cooling in high latitudes of the Northern Hemisphere, through regulating moisture in the Westerlies, exerts a dominate control on the paleolake evolution in the western Qaidam Basin. On a glacial-interglacial timescale, the region's climate also correlates closely with East Asian Winter Monsoon activity as recorded by the grain size variations in loess-paleosol sequences on the Chinese Loess Plateau. In particular, during glacial periods, some relatively warm/humid stages accompanied by high paleo-lake levels in the western Qaidam Basin are generally conformable with relatively weak East Asian Winter Monsoon,but exhibit less relations with marine benthic oxygen isotopes, North Atlantic Ocean sea surface temperature and East Asian Summer Monsoon. These observations collectively provide evidence that climate change in the western Qaidam Basin is,and was,not only controlled by the Westerlies, but also strongly influenced by the Siberian High, at least during glacial periods. The potential driving mechanisms may be a direct injection of cold air masses linked with an enhanced Siberian High into the basin through low altitude mountain passes (ca. 3000 m) particularly during glacials/stadials, or an indirect influence of the Siberian High on the moisture content of the Westerlies, and/or the position of the Westerly jet stream. The spatio-temporal impact of the Siberian High now needs to be assessed further across the northern Tibetan Plateau.