Abstract: Vulnerability(harmfulness) is an important part of debris flow risk assessment. Two methods are combined for the vulnerability assessment. The objective entropy value method is adopted to judge the relative importance of indexes; while the catastrophe progression to calculate its value. The well-grounded method theory can avoid the disadvantages of determining index weight value. Taking the vulnerability assessment examples of 10 debris flows in the geohazard surveying and zoning in Helong City, Jilin Province, for verification, the results show that the process of data acquisition, standardization and assessment is simple, and the mild and moderate-dominated vulnerability grades are consistent with the actual situation. The method can be more reasonably applied to practical work after improving the index system. Therefore, the combination of entropy value method and catastrophe theory is feasible and reliable for debris flow vulnerability assessment.