Abstract: The Hualong Basin in the northeastern margin of the Qinghai-Tibet Plateau has a huge thickness of Paleogene-Neogene clastic rock formation, which completely records the process of plateau uplift, paleoclimate and paleogeographic evolution. At the same time, its geological characteristics are related to the development and utilization of regional groundwater resources and engineering construction. In this paper, the lithology composition, fracture pore water quality and salt content of clastic rocks in the basin are investigated, analyzed and comprehensively studied from the perspective of hydraulic ring geology, and the ancient sedimentary environment is preliminarily discussed. The results show that the Paleogene-Neogene clastic rocks in Qunke-Jianzha Basin are mainly glutenite, mudstone and sandstone. The salinity of fracture pore water is 0.25~1.52 g/L, and the hydrochemical types are mostly HCO3-Ca, HCO3-Na and HCO3-Ca·Mg·Na. The salt content of clastic rocks is 0.13 %-0.18 %, which belongs to non-saline rock. The clastic rocks in Xunhua Basin are mainly sandy conglomerate and mudstone, containing gypsum rock. The salinity of fissure pore water is 0.24~10.65 g/L. The hydrochemical types are mostly HCO3·SO4-Na·Ca, SO4·Cl-Na or SO4·Cl-Na Ca. The salt content of clastic rock is 0.19 %~1.65 %, which is mostly saline rock.Combined with the previous research and analysis of the paleoclimate and paleogeography of the Cenozoic clastic rocks in the Hualong Basin, it is considered that the paleoclimate of the whole basin during the Eocene, Oligocene and Miocene was characterized by aridity. In the paleogeographic location, the Xunhua Basin is closer to the center of the basin and is in the terminal lake environment of concentration and strong evaporation, while the Qunke-Jianzha Basin is located at the edge of the basin and is in the circulation environment with better recharge, runoff and discharge conditions. This conclusion has certain reference value for the study of human drinking water in arid and water-deficient areas of Northwest China, engineering construction and basin paleoenvironment.