Abstract: For problem that tri-prism model cannot accurately represent irregular stratum structure especially borehole deviation, a 3D modeling method of bending zone in overburden strata based on generalized tri-prism model was proposed. Firstly, 3D geological model of overburden strata before mining is constructed based on the generalized three-prism model by use of drilling raw information. Then range of bending zone is determined through distinguishing key strata position. Finally, deformation parameters of the bending zone in overburden strata are estimated to modify the 3D geological model of overburden strata before mining, so as to establish 3D geological model of bending zone in overburden strata after mining. The example analysis result verifies validity of the method.