Abstract: Due to the one-side suspending of rock mass in mining stope, the stress from overlying country rock changed from three-dimensional stress state into two-dimensional stress state. With the face advance under the working of secondary stress, in overlying rock mass will appear tensile region and plastic region. Therefore, the criterion of destabilization by rock creep fracture has been brought forward to figure out the tensile force region, plastic fracture region and . O-outlined circle range on roof. The experiment in this essay is based on the geologic informatics of the coal mine in Bai Jiao and to set up a 3-D Structural Model with 3D-σ finite-element software. By the application of stress criterion and numeric analysis, he tensile force region, plastic fracture region and . O-outlined range on the roof were defined out. The essay also analyzed the evolvement of tensile force region with different paces, plastic region, O-outlined circle and roof sedimentation. The results will provide theoretical proof for stress calculation and control of mining stope.