In order to investigate the evolution of marine sedimentary environments during the Jurassic-Cretaceous transition in the Gyangzê area, South Tibet, we collected samples from the Jiabulagou section, and performed major, trace and rare earth element analysis. The discrimination diagrams (Fe2O3+MgO vs. TiO2 or Al2O3/SiO2) showed that, from the Late Jurassic Weimei Formation to the Early Cretaceous Jiabula Formation, the tectonic setting in the study area is mainly oceanic island arc. The index elements of Mn, Fe, V, Co, Ni and REE, and U/Th, V/Cr, Sr/Ba, Lan/Ybn and V/(V+Ni) ratios showed that the deposition conditions evolved from the Weimei Formation environment, characterized by shallow sea, oxygen-enriched, high-salt and high deposition rate, to the Early Cretaceous Jiabula Formation environment, featuring deep sea, water stratification and decreasing sedimentation rate, with obvious characteristics of deep sea sedimentary environment. The geochemical data were consistent with tectonic discrimination diagram, i.e., shallow sea facies sediment, indicated by sandstone in the Weimei Formation, and siltstone in the lower and calcareous mudstone in the upper Jiabula Formation, experienced water changes from shallow to deep. © 2020, Editorial Office of Earth Science Frontiers. All right reserved.