The practices of the exploration and development of shale gas in the Sichuan Basin in recent years show that deep-water shelf facies and good preservation conditions are key factors for shale gas' enrichment and high yields. Meantime, the drilling results of shale gas wells targeting the upper Paleozoic marine shale indicate a phenomenon that high production wells have abnormal high pressure, while low gas production wells have normal to low pressure. Shale gas' production and pressure coefficient show positive correlation. Based on qualitative assessments of shale gas, many researchers concluded that areas where shales are buried moderately, covered and bedded by proper rocks, and are far away from large open faults, uplifts, or erosion areas, as well as the places where there exists short period of tectonic movements and good structural patterns are the places that possess good preserving conditions. Based on the drilling data of marine-shale wells within southeastern Sichuan Basin, the authors revised the Fillippone formula and generated a new formula for predicting pressure coefficient which fits better to this region. With DS area as an example, this paper illustrates the prediction of the pressure coefficient of the Wufeng-longamxi Formation through a high-resolution inversion, and the result turns out to be good.