A novel ranking method of intuitionistic fuzzy value(IFV) which fuses the information of targets in multiple times is proposed aiming at the threat assessment problem in the air defense operation. Firstly, the subjective attribute weight and the objective attribute weight are integrated to structure the comprehensive attribute weight. Then, the technique for order preference by similarity to ideal solution(TOPSIS) is utilized to characterize the amount of information of IFVs, and the intuitionistic fuzzy entropy is calculated to measure the reliability of information. The amount and the reliability of information are integrated considering the decision makers’ risk attitude, and a novel ranking measure for IFVs is developed and used for the threat ranking of targets in single time. Finally, the decision information in multiple times is fused by the structured time sequence weights, whose form is Poisson reverse distribution, to get the final ranking. The simulation results show that the proposed method possesses properties of reliability and flexibility by synthesizing the decision information in multiple times and is able to be adjusted according to the decision makers' risk attitude.