Abstract: Since the 1990s, we have act as a administrative district unit of geological disasters investigation in the 1:500000 to 1:50000,which provides the scientific proof for geological disaster prevention planning and land use planning. Geological disasters in small watershed have a serious threat to urban construction and development in recent years. This paper studies pregnant environment, disaster evolution pattern and rule of geohazads in combining with geohazads investigation in Sunshui river watershed. The main conclusions are as follows：(1)on August 31, 2012, once-in-two-century heavy rainfall hit Sunshui river basin, rainfall of 149.2mm, which induced a large number of geohazads and showed a large number, big size, high density and a line-belt-sheet space distribution characteristics.(2)Spatial distribution is shown as：linear concentrated distribution along the important traffic trunk, such as ChengKun railway, county roads, rural roads; strip concentrated distribution along both sides of the river; the distribution of geological disaster is group.(3)the precipitation effect is obvious by time distribution controlling; the formation of geological hazards and rainfall, rainfall duration, rainfall intensity and the process was a positive correlation. Heavy rain is one of the main factors for the formation of geological disasters, and the ripple effect often forms the disaster chain, and clusters of disasters.(4)Heavy rain disaster chain patterns mainly include：rainstormlandslidebarrier dambarrier dam failurefloods; rainstormdebris flowbarrier dambarrier dam failure floods; rainstorm abandon slaglandslide or debris flow; rainstormbank slope failure buried and high harmony channel.