Ganjiagou is one of the famous debris flow disastrous gully in China. The catchment area is 24. 3km￣2.There are52 landslides and 1 3.4 13 × 10￣7m￣3 loosened solid material in the gully.The formation condition of debris flow is extrernely advantageous,In order to protect the farmland villages and towns,roads and Wudu city in upper reach,onecomprehensive prevention countermeasures has been put forwards according to formation features and disastersforms of debris flow,which is to combine the engineering and biological measures,to take engineering measure asthe domirant factor and to combine the regulating and drainly measures,taking regulating measure as the domirantfactor。