In order to evaluate the decision-making efficiency of different UUV clusters in target approaching and detection tasks,the decision-making flexibility of the UUV clusters when the measured target adopts different strategies is analyzed. Five indexes are proposed to evaluate the decision-making efficiency of UUV clusters:mission preparation time,cluster response time when the target stops,turns,turns back,and accelerates. The evaluation index system is established. Based on the existing test results,the lexicographic method is used to evaluate the decision-making efficiency of 5 types of UUV clusters,and the advantages and disadvantages of this method are analyzed,which provides research ideas for decision-making efficiency evaluation of different types of UUV clusters.