The Mesozoic and Upper Palaeozoic have good hydrocarbon source rocks in Subei Basin. In order to understand the distribution of the underlying Mesozoic and Upper Palaeozoic in this area, the authors tried to adopt forward and inversion technologies to predict the contact relationship of upper and lower formations of Indosinian unconformity. By using drilling data, 1D forward model was established to accurately calibrate Indosinian unconformity. Then the 1D forward model was applied to carry out seismic attributes extraction, coherence analysis and cluster inversion. Finally, the contact relationship of upper and lower formations of Indosinian unconformity without well data was inverted by that of the area with wells. The result matches well with the neighboring area.