The Minjiang fault zone consists of two faults with different property: an early thrust fault and a late normal fault. Field survey found that remnants of lacustrine deposits possibly aged Early Pleistocene, develop along the western side of the Minjiang Upstream, western Sichuan. The authors consider that the seismicity across the Minshan Mountains uplift seems to be not controlled by the Minjiang fault, but by the geometry of a deep décollement zone beneath the Minshan uplift. Such a thrust style may be the main deformation mechanism for late Cenozoic mountain building and fast uplift of the eastern margin of the Tibetan Plateau.