Abstract: The Adatan basin located on the southwestern margin of the Qaidam basin is sensitive to tectonic stress field of the orogenic belts in the surrounding areas and has abundant deformation records.The basin and the Altyn Tagh fault zone have been together under the unified left-lateral strike-slip shear stress and corresponding structures were generated and well-preserved since the middle Cenozoic.Through analysis of the sedimentary formation, properties of faults and regional structures in the basin, it can be inferred that the southwestern margin of Qaidam basin was under the S-N compression during Eocene and changed to left-lateral strike-slip stress in Oligocene.Also there probably was oblique push from the Tarim massif on the southwest margin of the Qaidam basin.Through deposit and structural sequence analysis in the basin, staged an evolution model of the Paleogene tectonic activities.