Abstract: Transmitted light and fluorescence microscopy observations of fluid inclusions indicate that fluid inclusions are widespread in the Permian Longtan Formation in Huangqiao area of the Lower Yangtze Basin, mainly aqueous and oil inclusions. They usually distribute in small sizes in quartz cracks and quartz secondary enlargement edges. Oil inclusions show yellow-green and blue-white fluorescents respectively with blueray and ultraviolet excitations, thus indicating that the oil in the Longtan Formation in the study area is primarily in middle mature stage. Through the microscopic temperature measurement of inclusions, combined with the burial history-thermal history, tectonic evolution and diagenetic evolution model researches, it has been concluded that the homogenization temperature of inclusions has 3 intervals, 89-93, 115.4-126.3 and 135-147.6℃. Hydrocarbons in the Longtan Formation in Huangqiao area have experienced 3 major filling periods: the first period for 73-70 Ma (the Late Cretaceous), the second period for 58-52 Ma (the Early Paleogene), the third period for 45-38 Ma (the Middle Paleogene). The second and third stages are most important.