Seismic prediction of formation pressure is of great significance to the evaluation of powerful gas-producing areas and exploration and development of shale oil and gas reservoirs. The study area of western Chongqing is a favorable area for exploration and development of deep shale gas. The shale gas resources in the area are abundant, and formation overpressure is common in the reservoirs. However, due to complex geological conditions, it is difficult to accurately obtain the formation compaction background trend while using conventional formation pressure seismic prediction methods, making it difficult to properly solve the seismic prediction of formation pressure. Usually, the formation compaction background trend is obtained directly through well trend fitting. The established formation compaction background often has large errors, resulting in inaccurate formation pressure prediction. Therefore, this paper constructs the formation compaction background trend through actual logging analysis, based on rock physics theory and rock physics model, which effectively improves the modeling accuracy of formation compaction background trend. By substituting the normal compaction background trend and measured parameters constructed by petrophysical modeling into the bulk modulus equation, the seismic prediction of formation pressure of the study area of western Chongqing in the Sichuan Basin is achieved, and good application results are achieved. By comparing with the actual drilling measured results, it is found that the predicted formation pressure parameters are consistent with the measured formation pressure parameters of multiple wells, indicating the applicability and accuracy of the method.