Abstract: The seismic predrilling pressure prediction is to calculate formation pressure by use of seismlc velocity data. According to the compaction principle, superpressured formation or overpressure always occurs with high porosity. As a consequence, it also corresponds to seismic low - velocity anomaly. It is vital important for new acreages without drilling data supply to predlct the existence of superpressured formation, estimate its pressure by means of selsmic and provide reference data for drilling engineering. This paper corrected the empirical equations of interval and average velocity and verified them in association with the seismic data on Yaha area.