Abstract: Based on the data of tectonic geometry and kinematics, oil and gas exploration seismic profiles, seismic sounding reflection, seismic tomography and geothermy, the authors bring forward a conception model of coupling mechanics of the Tarim block＇s and the Junggar block＇s lithosphere mantles collision and delamination under the Tianshan Mountains. Due to India-Asian collision, the north frontier lithosphere mantle of the Tibet Plateau collided with the Tarim lithosphere mantle in V-shape, which pushes the high strength Tarim lithosphere to move northward and to subduct horizontally under the Tianshan Mountains. The subducted lithosphere mantle of the Tarim block collided with the southward subducted lithosphere mantle of the Junggar block and then delaminated in the back peel style under the Tianshan Mountains. While the Tarim block lithosphere mantle was subducting, the Kuqa rejuvenation foreland basin and rejuvenation Tianshan Mountains were formed. The thrust slip in the Kuqa rejuvenation foreland thrust belt accounts for 20% of the Tarim block subduction. This basin and mountain coupling mechanics model may reasonably interpret the features of the basin structures, basin depression, mountain uplift, lithosphere structure and geothermy in this region.