Aiming at the problem of radiator threat evaluating in radar countermeasures field, an objective weight distribution method based on Shapley value is used to overcome the advantages of subjective assignment and not relying on prior knowledge. Combined with TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution), a radiator threat assessment model based on ShapleyTOPSIS is proposed. Firstly, the evaluation matrix of target set and attribute set is constructed by distinguishing benefit type and cost type and standardize the attribute indexes. Then, the advantage relation is used for attribute reduction, and the weight of each attribute is determined based on Shapley value, and the attribute weight is used to update the evaluation matrix. Finally, the positive and negative ideal solutions of the model were obtained, and the proximity degree of each radiator was solved respectively, and the threat ranking of radiator was conducted. The simulation results show that, compared with TOPSIS model based on expert system assignment, the model in this paper comprehensively considers the relationship between various attributes, and the result of threat ranking is more accurate.