For the importance of the aircraft antidamage ability assessment and the complex and fuzziness of the antidamage ability assessment, the assessment method of the aircraft antidamage ability based on adjacent important degree with entropy weight is proposed. The aircraft antidamage ability evaluation index system is built from four aspects of the sensitivity, vulnerability, the injuries to repair and combat capability, by using adjacent important degree and entropy weight to determine the subjective and objective weights. The antidamage ability evaluation model is presented according to the property of the evaluation indexes. Through the numerical example verification, it shows that this method is high maneuverability, high application value and easy to implement. The evaluation results are more objective, and the problems in the evaluation of the aircraft antidamage ability can be effectively solved.