Abstract: In the aim of predicting debris flow in Jixian county of Tianjin, some townships in the county were taken as study area, and area grid was automatically divided, then the node-cell-channel information was generated. By analyzing the formation conditions of debris flow, 7 risk factors of debris flow were selected ,namely occurrence frequency of debris flow, 24 h rainfall, 1 h rainfall, geological lithology, average slope gradient, vegetation cover type and population density. In association with fuzzy weighting method, the weight of each risk factor was calculated and a prediction model of debris flow was established. Furthermore, the debris flow occurred in Shuang’an area of Jixian county in 2012 was simulated according to the calculated risk level of each grid. Results show that in the northern mountainous area of the county, the hazard degree of debris flow R_d varies from 0.4 to 0.8, indicating medium risk and high risk. The hazard point of Shuang’an debris flow is located at a high-risk area, and the simulated results are in accordance with the actual conditions. The model has certain reliability and can be used to forecast the debris flow in the mountainous area of northern Jixian county of Tianjin.

Key words: debris flow, risk factor, weight, fuzzy weighting method, forecast model