Abstract: Confirmed by various well drilling,abnormal high pressures exist in deep formation of Bozhong area in Bohai oilfield,while seismic data quality is poorer there and the pressure prediction accuracy is difficult to be improved.Therefore,the formation pressure prediction method based on the technology of effective stress has been adopted.By considering the effect of overlying strata pressure,the relationship between formation pressure and effective stress is used to predict abnormal formation pressure.This method does not need to set up speed change trend line,its precision is relatively high,and the results are a three-dimensional pore pressure.Example analysis shows that the method accuracy is higher and has achieved good application effect.