The evaluation model based on Vague theory is established to solve the problem of assessing radar seeker jamming effectiveness, in which the situation that multiple persons involved in the decisionmaking has been taken into consideration, and a big improvement has been made. Firstly, Vague sets which deviate from the ideal decisionmaking Vague sets severely are removed, in other words, the “outlier” is ruled out based on the concept of distance between Vague sets. Then the comprehensive decisionmaking Vague sets are defined. In order to acquire the final evaluation result, the comprehensive decisionmaking Vague sets are dealt with the improved evaluation algorithm. Finally, the feasibility and superiority of the method is proved by giving the example of crosseyed jamming effect evaluation.