The organic reef formation and distributed scale are controlled by the Kaijiang Liangping” trough palaeogeomorphology formed at the end of Longtan” perioand sustained sea transgression during the “Changxing period in the eastern part of Sichuan Basin. The platform margin facies on both sides of the “Kaijiang Liangping” trough are the favorable regions of organic reef growth. Different facies of “trough foreslope buildup platform” at the “Changxing” period are identified using 2D and 3D seismic profiles in combination with the reflected shapes of the stratigraphic top of Changxing Formation and the time diffe rence between top and bottom in the Changxing Formation strata. The organic reefs are mainly distributed in the rock crown of the seismic profiles. The shape of organic reefs and their distribution can be predicted and carved by using techniques of amplitude slice and coherent slice in the 3D seismic profiles. Based on the techniques above, the expected results have been achieved in the gas fields of Wubaiti and Gaofengchang.