Abstract: In order to identify urban comprehensive disaster risks more systematically and solve the problem of inconsistent evaluation results of different single methods, a combined evaluation method based on the concept of SD was proposed. Firstly, a comprehensive disaster risk evaluation index system was established based on the criteria of disaster risk, economic and social vulnerability and urban fortification, and six single methods were used for basic evaluation to obtain a single evaluation result. Then, the similarity matrix and the difference matrix of the evaluation results of different methods were calculated by vector included angle cosine and Euclidean distance respectively, and an SD combination evaluation model integrating similarity and difference was constructed to evaluate 31 provinces, municipalities and autonomous regions in mainland China. The results show that SD model can well overcome the inconsistency of different single evaluation results and embody the new combination idea of "seeking common ground horizontally and seeking differences vertically", which makes the comprehensive urban risk evaluation results more objective and reasonable and provides theoretical and practical basis for in-depth identification of the comprehensive urban disaster risk level.

Key words: comprehensive disaster risk, combination evaluation method, support degree (SD), similarity, different degree