[Objective] Studying the control effect of Yuanmou fracture on debris flow in Dongshan area, to provide scientific basis for debris flow control in this area.[Methods] Based on the investigation of the valley along the Dongshan area, the control effect of Yuanmou fracture on Dongshan debris flow gully was studied.[Results] The relative position of debris flow gully to Yuanmou fracture has influences on the development of the debris flow, which can control the formation of Dongshan topography and geomorphology, can control the lithology and engineering characteristics of Dongshan formation and can control the formation of climate in Yuanmou County.[Conclusion] The Yuanmou fracture plays a controlling role in the formation of debris flow in Dongshan area, the frequent debris flow in Dongshan area can be attributed to it.