Abstract: The exploration degree at the southern margin of Junggar basin is very low and the calculation accuracy of formation pressure with logging data is not satisfying, especially for pressure prediction of undrilled formations in deep piedmont structures. Therefore, taking Xihu anticline?Dushanzi anticline in Sikeshu sag as an example, 2D interval velocity is obtained on the basis of logging constraint inversion of the 2D seismic data and the seismic interval velocities are effectively extracted in the 2 ultra?deep wells such as Dushan 1 and Xihu 1. A 2D formation pressure model is established by using spatial interpolation algorithm and formation pressures in individual wells, then formation pressures in regional spaces can be calculated based on the 2D interval velocity. The spatial distribution of formation pressure is obtained through visualized description and analysis. The comparison of the results predicted by the model with the field testing pressures shows that the prediction accuracy is higher than 85%. The seismic?logging combination method to forecast pressures in deep and complex formations could provide scientific basis for well bore structure design, safe drilling fluid density window determination and efficient drilling operation.