Abstract: A relative different function of the variable fuzzy theory was introduced to the building of a sensitivity analysis model for debris flow. 11 debris flow catchments located in Chifeng pumped storage power station in Inner Mongolia were investigated. Seven major factors， namely， loose material volume per square kilometer， loose material supply length ratio， average gradient of the main channel， average hill slope， drainage density， curvature of the main channel， and poor vegetation area ratio， were selected for debris flow susceptibility analysis. Precedence chart was used for objective weighting and entropy method was used for subjective weighting. Combination weighting was calculated by game theory. Combination weights of major factors for the investigated 11 debris flow catchments are 0.19， 0.14， 0.19， 0.10， 0.09， 0.18 and 0.11， respectively. Susceptibility results show that the susceptibility of 6 debris flow catchments are very low and 5 are low. Comparing the susceptibility results with field observations， 11 debris flow catchments agrees very well with real status of debris flow， proved the feasibility of this method.

Key words: debris flow, combination weighting, susceptibility, relative different function, assessment model