Abstract: The reef?flat carbonate reservoir of Changxing formation in Yuanba area in northeastern Sichuan basin is characterized by average buried depth of 7 000 m, thin in thickness, serious heterogeneity and superimposed P?wave impedance between reservoir and non?reservoir intervals. So the seismic P?wave impedance inversion after poststack can not meet the needs for integration of exploration and exploitation at present. In order to get a high resolution predictable reservoir characterization and reduce the uncertainty of such a prediction andthe drilling risk, the study of prestack geostatistic inversion is carried out by fully using available seismic information. This method integrates with seismic AVO information, well logging and geological recognition, including petrophysical modeling, geological frame model and seismic data restriction, prestack geostatistic inversion. Finally, the lithologic inversion profile is obtained. The result shows high vertical and horizontal resolution and reliable lateral prediction, which allows the inversion and prediction of thin reservoirs to be effectively realized, thus improving the precision and reducing the risk of reservoir prediction