Abstract: Research on the regional tectonic stress field during the Late Jurassic to the Early Cretaceous and Late Cretaceous to Early Tertiary in the northwest of China shows that the state of stress field to the east of Aerjin Fracture is different from the that to the west of Aerjin Fracture.The principal compressive stress of the regional tectonic stress field is NNE-oriented to the east and near-meridional to the west of Aerjin Fracture during the Late Jurassic to the Early Cretaceous.In Late Cretaceous-Early Tertiary,the regional tectonic stress field to the east of Aerjin Fracture basically carry on the state of previous stress field and the direction of the principal compressive stress to the west of Aerjin Fracture is northwestward.This tectonic stress field feature is consistent with the basin prototype,basin reversal and tectonization forming in the relevant period.