Abstract: Based on analyses of homogenization temperature,salinity and density of fluid inclusions in core samples from wells in the northeast of Sichuan Basin,there are 3 stages of hydrocarbon fluid activities in the region.Homogenization temperature,salinity and density of fluid inclusions are closely related.When ancient and present geothermal gradient changes are small,measured fluid inclusion homogenization temperature and palaeogeothermal gradient can be used to calculate the maximum burial depth or corrosional thickness,so as to restore thermal evolution history.Homogenization temperature of fluid inclusion,R_o,measured strata temperature and illite crystallinity are also closely related.They are direct and effective index used in thermal evolution history restoration in high mature marine facies regions.