Abstract: The recognition of unconformities and their properties and intensities is of significance for understanding the tectonic history and petroleum accumulation regularities in Ke-Bai area, northwestern margin of Junggar basin. Seismic data show that there are several unconformities, reflecting several times of tectonic movements, of which, four times of tectonic movements played important roles in the formation of the structures in Ke-Bai area. The first occurred after sedimentation of the Middle Permian Lower Wuerher Formation, showing the lower and Middle Permian titling toward the southeast to be eroded; The second occurred at the end of the Triassic, affecting the area from the Dazhuluogou fault to Baikouquan in the hanging wall of Ke-bai fault; The third occurred at the end of Middle Jurassic, showing thrust faulting with gentle folding in the Ke-Bai fault and its hanging wall; The fourth occurred at the end of the Early Cretaceous, showing titling with weak faulting and folding. The differences in deformation of various periods and different areas in Ke-Bai area are closely related with the geodynamic conditions.