In order to solve the problem of quantize qualitative indexes in the evaluation system of aircraft battle damage repair (ABDR) efficiency properly, an extension entropy weight method is proposed to achieve scientific and objective indexes’ weights. According to extension interval number and its operation rules, the entropy weight method is improved by the extension theory. In view of the shortage of the entropy weight method, combined with extension theory, considering the uncertainty of quantizing qualitative indexes, ABDR efficiency assessment model is proposed. Based on benchmark extension interval, the entropy weight of the indexes is sorted. The proposed model is validated by the application of ABDR efficiency assessment. The results indicate that the model is effective and feasible.