The objective of this study is to predict the pore pressure using seismic acoustic impedance in one of carbonate oil field in the southwest of Iran. The proposed prediction method is the one of the new methods for estimating pore pressure which based on the principles of Bowers method constructed directly between seismic acoustic impedance and effective stress. However, it is avoids using seismic conversion velocity. In this manner, acoustic impedance cube data were produced from inversion of seismic data and interpretation of horizons using well logs and seismic data. Then overburden pressure was estimated from the density cube. Thereafter, an initial relationship has been obtained from the effective pressure and acoustic impedance data fitting that have been calibrated with test-well data. Then, seismic acoustic impedance cube was converted into effective pressure. Finally, pore pressure cube was calculated by Terzaghi equation. The correct separation of the reservoir layers in the cross sections and high correlation coefficient between these data and the well tests pressures shows that the performance of acoustic impedance method in the pore pressure prediction before drilling for Carbonate reservoirs is acceptable.