Abstract: The environmental evolution in the northern South China Sea since the last interglacial stage was studied by means of the oxygen isotope of planktonic foraminifera, and the paleontology of foraminifera and diatom of the Core ZSQD196PC,which was sampled on a slope in the study sea.According to the percentages of important species,individual amount and assemblage characteristics,3 foraminifera assemblages and 4 diatom assemblages corresponding to the known foraminifera oxygen isotope stages are subdivided.The foraminiferal fauna are dominated by warm-water species in MIS1,and the percentage of Pulleniatina obliquiloculata is significantly high,while the diatom flora are dominated by tropical plankton species.During the period in MIS2~4 stages, the foraminiferal fauna are dominated by cold-water species,and the percentage of thermocline species is relatively high;the diatom flora are dominated by tropical-subtropical plankton and coastal species.According to the comparison to the planktonic foraminiferal oxygen isotope,we discussed the responses of sedimentary environment evolution to the Last Glacial Maximum and the events of Bølling-Allerød and Younger Dryas as well as the climate changes during the last glacial stage.