The evaluation system of smart ammunition warhead overall efficiency has been established in this paper. All kinds of evaluation methods have been analyzed. Having led the concept of hierarchical structure into technique for order preference by similarity to ideal solution (TOPSIS) method, we put forward the step TOPSIS method which is suitable for evaluating the overall efficiency of smart ammunition warheads. In the calculation of index weight, the graded weight calculus is put forward which hardly relies on the subjectivity of decision-makers and can reflect the sensitivity and compatibility of the index. In the graded weight calculation, the proportional-arithmetic weight value calculus and sensitivity-compatibility weight value calculus are given respectively.