The Surface rupture of Beichuan--Nanba--Linanshi Fault, which is the northern seg- ment of Longmenshan tectonic belt is studied. Observation at Huangjiaba,Guixi, Pingtong, Nanba and Shikanzi suggests that the surface ruptures on this segment spread continuously along the trend of the fault with N45°-65°E in general. The rate of vertical offset and horizontal offset become small from Huangjiaba（2.8：1） to Shikanzi {0.9：1）. Features of surface rupture indicate that the fault movement is thrusts with dextral strike-slip. Distribution of aftershocks indicates that the area between Beichuan--Nanba--Linanshi Fault and Qingchuan Fault probably have a buried active fault.