Nowadays, the methods of determining the index weights of aerial target threat assessment for warship formation are unreasonable. On the basis of designating the improved target threat assessment indicators, the combined index weights of threat assessment is determined by using IAHP and the entropy method respectively, so as to get the index weights of threat assessment. Considering the characteristics of warship formation, the aerial target threat assessment models of the warship and the warship formation are proposed based on the improved TOPSIS method. The model is suitable for warship formation to make aerial target threat assessment under cooperative combat environment. Finally, a simulation example is given to demonstrate the effectiveness of the model.