The threat assessment of aerial targets is the basis for improving the ability that air defense system deals with various objects. Considering the timeliness, multi-factor and imprecision in a threat assessment process, a group generalized intuitionistic fuzzy soft sets (G-GIFSS) is constructed to fulfill the threat assessment. Among them, after selecting suitable evaluation indexes and quantitative methods, a multi-expert parameter set is introduced to overcome the knowledge limitation of the only one expert in original GIFSS. Finally, the feasibility and effectiveness of the proposed method for threat assessment is verified by comparison with other state-of-the-art decision methods on a practical instance.