Abstract: In the Longtan Formation of the Upper Permian in Huangqiao region of the Lower Yangtze Basin, there are 2 stages of fluid inclusion. The fluid inclusions of stage Ⅰ mainly generated during the early-middle period of quartz overgrowth, and generally located along micro-fractures within a linear zone. The fluid inclusions of stage Ⅱ mainly generated after quartz overgrowth, and distributed along micro-fractures which cut through quartz overgrowth. The homogenization temperature of fluid inclusions was 75-120℃, and the peak was 75-85℃. Analyses of geothermal evolution, burial history and hydrocarbon generation-expulsion history revealed that the main hydrocarbon generation period of the Longtan Formation source rocks was in Cretaceous, and oil charging mainly occurred in Jurassic (188-160 Ma) and from the Late Cretaceous to Paleocene (60-43 Ma). The Longtan reservoir mainly formed at the end of Cretaceous.