Abstract: In terms of three-way decision models based on decision-theoretic rough sets, the loss function is difficult to determine and rational. Considering the adaptability of interval-number analytic hierarchy process in dealing with multi-attribute decision-making problems and the tolerance of matrix error, the steps of determining the loss function based on interval-number analytic hierarchy process are given, and the effectiveness of the loss function is proved. It is applied to an example of air combat target threat assessment, and the assessment results are explained from the perspective of three decision-making. The example analysis shows that the loss function determined by this method is reasonable, the threshold pair is more compact, the uncertainty caused by data error is reduced, the risk of wrong decision is reduced, and it meets the needs of modern information air combat.

Key words: three-way decisions, decision-theoretic rough set, loss function, interval number analytic hierarchy process, air combat target threat assessment