A better understanding of the tectonic relationship between the Lijiang- Xiaojinhe fault and the Longmenshan fault belt is urgent as the devastating 2008 Wenchuan earthquake hit the eastern Tibetan Plateau. However, related researches are rare especially along its northern segment due to the poorly preserved Quaternary sediments. Fault zone structure contains valuable information about the faults historical activity which potentially provide an alternative way to analyze this problem. Here we focus on outcrops along the Yanyuan section on the northern segment of this fault. Based on detailed field survey, X- ray diffraction and microstructure analyses, we find the damage zone is characterized by an over 20 m thick fracture zone. Strikes of the fracture cluster in the range of NE20°~30° and are interpreted as the extensional shear texture associated with the left- lateral Lijiang- Xiaojinhe fault. Fault rocks are mostly fault gouge and breccia in the fault core. Clay minerals in the limestone fault breccia are mainly illite and illite/smectite formation, whereas they are palygorskite and clinochlore in the siltstone fault gouge. Structures uncovered in both the outcrop and the micro- section show angular fragments with different grain size scattered in the fine grained matrix, showing that the northern segment of the Lijiang- Xiaojinhe fault is stick- slip rather than creep. Furthermore, the measured thickness of fault rock is 5~8 m which is considerably smaller than the reported 180~280 m and 40~50 m of the Yingxiu- Beichuan fault and Anxian- Guanxian fault among the Longmenshan fault zone, respectively. The historical activity of the Lijiang- Xiaojinhe fault is much lower than the latter, and their seismic behavior are also not analogous. Taking into account the difference in fault zone structure, composition and categories of the fault rock, as well as the slip behavior and amount of uplift- denudation they indicated, the Lijiang- Xiaojinhe fault was higly possible formed much later than the time that the Xianshuihe fault offseted the Jinpingshan- Longmenshan thrust belt. It might have a totally different history of active from the major faults in the Longmenshan fault belt over the late Cenozoic.