Dextralslip thrusting of major active faults in Longmen Mts. caused the MS 8.0 Wenchuan earthquake, which resulted in huge hazards to local people. Typical examples presented here are seismic hazards of the MS 8.0 earthquake, geological hazards triggered by the earthquake and potential geological hazards induced by the earthquake in Longmen Mts. The heavy seismic disasters in Wenchuan includes building collaping, moving and tilting of houses, wall fracturing, and breaking or even collapse of bridges. Geological hazards triggered by the Wenchuan Earthquake include landslide, rockfalls, local debris flow and liquefaction. Potential geological hazards include latent landslides and debris flows, rockslides and rockfalls along unstable slopes. Distribution of seismic and geological hazards are closely related to active faults, with the worst hazards occurring along and near the BeichuanYingxiu fault in central Longmen Mts., and along the minor seismic faults such as the HanwangXuankou fault in eastern Longmen Mts. and the MaoxianWenchuan fault and the Qingchuan fault in western Longmen Mts. Seismic and geological hazards greatly decreased in the areas 3~5 km away from the seismic faults.