Under the tropical and sub-tropical climatic background, northern Beibu Gulf is an interaction zone between cold and warm air masses and is the gulf closest to Indian Ocean in China resulting frequent climatic fluctuations. By comparison with neighboring areas especially northern areas' rich data and research results,the study on palaeoclimatic fluctuations since Late Pleistocene in northern Beibu Gulf and their characteristics have almost not carried out yet. The seismic profile interpretation and geological core sediments analysis have revealed that there were buried river channels during Quaternary under seafloor outside Qinzhou Bay Mouth, which formed during sea transgression in Holocene and had become the transition zone from submarine slope to submarine plain. There are main run offs now Fangcheng River, Maoling River, Qin River,Dafeng River and Nanliu River from west to east along coastline of Qinzhou Bay and its neighboring areas. This study obtained whole-length 80.05 m core sediments (core ZK9) from Quaternary strata to the upper surface of weathered crust through drill equipment in position of 21o24'20"N,108o33'57"E located at northern part of a sunken area outside the Qinzhou Bay Mouth by seismic interpretation. Based on 1 m interval, 13 sediments samples of Upper Pleistocene from 25.1 m to 9.7 m(103 ~11.5 ka) and 4 samples for age dating were analyzed and identified in laboratories in fundamental sedimentology of granularity, micro-geochemical elements, detrital minerals and micro-palaeontology and age measurement. The age dating results were 103 10 ka (25.1 m), 667 ka(20.8 m),626 ka(20, 2 m)by optical stimulated luminescence method (OSL) and 1159851 cal.a B.P.(10.2 m) by ~(14)C method respectively and the age frame was then established through linear interpolation. The study results showed that there were tropical and sub-tropical sporopollen species of Microlepia,Polypodiaceae,Castanopsis and so in this Upper Pleistocene core sediments, the dominant diatom species was Cyclotella striata and there wasn't any foraminifera found. The sediments composition was sand,silt and clay with pebbles in some depths, and the detrital minerals included quartz,feldspar,pyrite,ilmenite,limonite and so on with dominant quartz averaged 89.02% in concentration. The concentration of micro-geochemical elements ranged from 9.64 ~246.86 mug/g within which Ba reached the highest, and there were significant correlation between Co,Ni,Sr,Zn,Zr,Ga,Ba beside Cu and Cr which were more sensitive to oxidation-reduction condition. The study also revealed that the sedimentary environment was of fluvial/riverine facie with the characteristics of time or depth fluctuations and then divided into two primary stages: the Last Interglacial and the Last Glacial and further four climatic stages periodically. The Stage One 103 ~60 ka(25.1 ~19.6 m) was the Last Interglacial with fluvial facie and warm event, and Stage Two was divide into three sub-stages: Sub-stage One 60 ~46 ka(19.6 ~ 17.1 m) Early Ice Order with generally-low(hydrodynamic) energy, 46 ~19 ka(17.1 ~11.5 m) Interglacial Order with generally-high energy and 19 ~11.5 ka (11.5 ~9.7 m) Late Ice Order with generally-low energy. The above four climatic stages could be basically corresponded to palaeo-climates of same times in neighboring regions of Yun-Gui Plateau and South of Changjiang River.