Abstract: A large-scale accumulation body,named Jieyi compound accumulation body,is located in the left bank of Wunonglong Hydropower Station from elevation of 1,935 m to 2,225 m in Lancang River.Investigation and analysis results of the compound accumulation body show that it consists of collapse accumulation,debris flow accumulation and grait accumulation remaining in fluvial terrace with a multivariate structure from top to bottom.After expatiation of its genetic analysis,it can be seen that the compound accumulation body is stably supported by the rock foundation foundation below.