Tectonic- erosion- sedimentation interaction and their coupled relationships control the evolution of fold- and- thrust belts and foreland basin systems at different time and space scales. In this study, we use analog experiments to investigate the influence of erosion and sedimentation of fold- and- thrust belt, in particular, the along- strike change of erosion- sedimentation in the Longmenshan fold- and- thrust belt. The along- strike change of surface processes results in a strong erosion in wedge hinterland, reactivation of faults and out- of- sequence thrusting, some of faults join together along strike to form lateral faults (or transfer faults). Furthermore, along- strike change of erosion accommodates overturning of faults, even normal ones, in the wedge hinterland. Stronger the erosion, bigger the change for the faults in the hinterland. Extensional deformation is found across the Longmenshan fold- and- thrust belt, which could be accounted by the along- strike change of erosion that occurred in the Cretaceous to Cenozoic time. In particular, the along- strike change of erosion induces reactivation of low- angle faults, and out- of- sequence thrusting in the southwestern Sichuan basin. Thus, we argue that the tectonic shortening and surface processes have had a significant influence on the architecture of the Longmenshan.