Abstract: Some major problems were encountered in the application of conventional set pair analysis method: the assessment was too rough; the set pair potential could not handle the situation when c=0; large amount of useful information was lost during the judgment and appraisal of sample’s class. In order to overcome the above-mentioned drawbacks, we attempted to optimize and improve the conventional set pair analysis method by adopting the malleability of relation degree, the generalized set pair potential and the confidence criterion. We built an improved set pair analysis model for assessing the social impact of dam breach based on examining major factors of social impact and establishing an assessment index system. By applying this model to the social impact assessment of Liujiatai Reservoir dam breach and comparing the results with those of other methods, we found social impact assessment of the dam breach was at serious level and proved the reliability and rationality of the present model.

Key words: improved set pair analysis, social impact of dam breach, index system, assessment model, Liujiatai Reservoir