Abstract: The discovery of Permian hydrocarbon reservoir is of theoretical and practical significance for oil exploration in the Lower Yangtze region. It is not only the first discovery in the Palaeozoic in the region, but also a valuable case for the study of hydrocarbon accumulation model and reservoir-forming mechanisms in the upper group in later stage. The tight sand reservoir found at the top of the Longtan Group of Huangqiao block contains a substantial amount of CO₂. Based on the newly acquired seismic and well drilling data, plus the investigation of petrographic sections, physical properties, logging data and hydrocarbon fluid inclusions, we made an integrated study on the characteristics of the Neopaleozoic hydrocarbon reservoir and an accumulation model is proposed.