The evolution of karst basin plays a crucial role in earth surface processes, which well records the history of watershed erosion and chemical weathering. Rb/Sr has been widely used for revealing environmental information among different palaeoclimatic archives. In this study, based upon the 14C dates and characteristics of K and Ca in the Mawo karst basin sediments from Weining county of Guizhou province, the geochemical behaviour of Rb and Sr were analysed and Rb/Sr were compiled for the palaeoclimate in Northwest Guizhou. The results showed that concentrations of Rb in the four studied profiles were mostly greater than Sr, and strong positive correlations between Rb and K and between Sr and Ca were observed, which further confirmed the notion that Sr was more mobile than Rb in the evolution of Mawo karst basin. The vertical variation of Rb/Sr in all profiles suggested periodic sedimentary environment in the studied area, which corresponded to the field characteristics, especially the color variation of the sediments. High Rb/Sr primarily controlled by Rb indicated the arid climate or a low water level of the basin, otherwise the opposite. There existed 3〖SX(〗1〖〗2〖SX)〗 dry moist climate cycles in the past 40ka of the karst basin that could be used as ideal archive for reconstructing palaeoclimate in karst areas.