Abstract: The H Structure in Haizhong Sag of Weixi exploration area encountered high-yield hydrocarbon flows, with abnormal overpressure developed in Wei-3 and Wei-4 formations. Accurate pore pressure prediction is critical for ensuring safe and efficient drilling operations. Based on actual drilling data and geological understanding, this study reveals that the overpressure mechanisms in the area result from dual factors: undercompaction caused by rapid deposition in mudstone intervals and hydrocarbon-generation pressurization. Through velocity data optimization and comparative analysis of various pressure prediction methods, Eaton method with region-specific geological parameter adjustments was identified as the optimal model. The optimized model achieved a prediction accuracy of 93% for the Wei-4 formation in newly drilled wells, successfully guiding casing program design and drilling fluid density optimization, which ensured both drilling safety and reservoir protection. Practice demonstrates that optimization of velocity data and a thorough understanding of geological conditions are key steps to reliable pressure prediction. The Eaton-based method with parameters modified for the dual-mechanism (undercompaction and hydrocarbon-generation pressurization) exhibits good applicability to the abnormally pressured formations in this area.