The Daliangshan fault zone is the eastern branch in the central section of Xianshuihe-Xiaojiang fault system. It has been neglected for a long time, partly because of no destructive earthquake records along this fault zone. On the other hand, it is located on the remote and inaccessible plateau. So far it was excluded as part of the Xianshuihe-Xiaojiang fault system. Based on the interpretation of aerophotographs and field investigations, we document this fault zone in detail, and give an estimation of strike-slip rate about 3 mm/a in Late Quaternary together with age dating data. The results suggest that the Daliangshan fault zone is a newly-generated fault zone resulted from shortcutting in the central section of Xianshuihe-Xiaojiang fault system because of the clockwise rotation of the Southeastern Tibetan Crustal Block, which is bounded by the Xianshuihe-Xiaojiang fault system. Moreover, the shortcutting may make the Daliangshan fault zone replace the Anninghe and Zemuhe fault zones gradually, and finally, the later two fault zones will probably die out with the continuous clockwise rotation.Daliangshan fault zone, newly-generated fault, Xianshuihe-Xiaojiang fault system, southeast TibetThe arc-like Xianshuihe-Xiaojiang fault system can be divided into three sections. The northern, Xianshuihe fault zone, is a narrow tectonic zone; the southern, Xiaojiang fault zone, consists of two faults, which are parallel to and less than 20 km apart from each other; the central has more completed texture and higher fault density, presenting a spindle-like tectonic zone. The Daliangshan fault zone is the eastern boundary of the spindle-like tectonic zone (wide lines in the index of the Figure 1). Almost all of the previous researches were focused on the Xianshuihe fault zone, Xiaojiang fault zone and the Aninghe, Zemuhe fault zones, the western boundary of the central spindle-like tectonic zone. The eastern boundary of the spindle tectonic zone, Daliangshan fault zone, has been neglected for a long time and even excluded as the part of the Xianshuihe-Xiaojiang fault system in some researches [2][3][4][5] , partly because of no destructive earthquake records along the fault zone and partly because of its location on the remote and inaccessible plateau. The other important reason is that the Daliangshan fault zone is a newly-generated tectonic zone. The maturity of the newly-generated fault zone is lower than other faults in the fault system, and then the tectonic landform along the lower matured fault does not present itself as obviously as other faults. Based on the