3. Institute of Earth Sciences,China University of Geosciences (Beijing),Haidian Beijing 100083, China) The shale of Middle-Upper Permian in the Lower Yangtze area is an important source rock in the region, but the research on the elemental characteristics of different sedimentary facies is still lacking in the past. Continuous X-ray fluorescence(XRF) element scanning was performed on the shale core of the Middle-Upper Permian in Well Gangdi 1 in the Lower Yangtze area. The contents of main elements such as Si, Al, Ca, Fe and trace elements such as Sr, Rb, Ti and their ratios in the middle and upper Permian strata were analyzed, and the evolution characteristics of sedimentary environment were discussed in combination with the quantitative analysis of mineral composition of samples. The results show that the elements such as Al, Ti, Si and Rb, which have strong indicative significance for terrestrial deposition, have a high-high-low variation in the vertical direction. The Ca, Sr and other elements indicating marine deposits are mainly concentrated in the upper Dalong Formation, and the content of other layers is low, and there are abnormal values in some areas. The ratio of element content has a certain rule, among which Rb / Sr and Ba / Sr show a low-high-low trend. The maximum value of Al / ( Al + Fe + Mn ) ratio is 0.8, the minimum value is 0.4, and the average value is 0.71, which is generally greater than 0.6, indicating an important source of biogenesis. The Middle-Upper Permian belongs to the transitional-marine reduction environment. From bottom to top, the sedimentary environment changes from deep-water basin facies to deep-water shelf facies to sea-land transition facies to shallow-water shelf facies. During this period, the water body changes from deep-shallow-deep. Among them, the early stage of the Gufeng Formation is the deep-water basin phase, and then gradually enters the deep-water shelf phase. The Longtan Formation is dominated by the sea-land transition phase, and the relative sea level changes frequently during the sedimentary period. In the deep-water period, the lithology is dominated by self-deposited limestone, and the corresponding element Ca content is high. In the shallow water period, it is mainly light gray mud shale deposition, and the corresponding main elements change to Si and Al. After the short-term subsidence of the sea level in the Dalong Formation, the water body gradually deepened, dominated by continental shelf deposition.