Liujia gully is a narrow-steep and high-frequency debris flow gully which is located in Jinchuan county， Aba Prefecture， Sichuan Province. Every raining season，rainfall will lead to debris flow disaster chains. In this paper， the author analyzes the characteristics and the environment of debris flow on the basis of field investigation and field survey. Debris flow parameters under different rainfall frequency are calculated by the rain flood method. The paper also analyzes the possibility of debris flow blocking the main river （Kasa gully） to provide the volume weight required. Many difficulties in treatment of debris flow in narrow-steep gullies and are discussed with the case-dependent measures. The Wenchuan earthquake induced a great mass of collapse and landslide with unit-area loose solid materials in Liujia gully up to 98.11×10⁴ m³， and debris flow happened at higher frequency and amplifed volume at the average longitudinal slope of 409.8‰ leading to the formation of the valley disaster chain consisting of rain + runoff erosion-landslide-landslide dam-weir burst-increasing debris flow-barrier lake-hazardous Kasa gullies. To solve the disaster， we suggest comprehensive treatment measures which include using Gabion stone cage to stabilize the slope and the gully， construction of retaining dams and drainage canals. They can provide reference for treatment of high-frequency narrow steep debris flow disasters in small watersheds.