Aiming at the complex redundancy problem of indicators in the existing index system for evaluating the effectiveness of maintenance support of missile equipment， an index reduction method based on the improved Vague set is proposed. The method introduces the generalized advantage theory into the traditional Vague set theory， designs and constructs the Vague generalized advantage relationship model， and proposes the index reduction method based on the Vague generalized advantage relationship. Taking the whole system of evaluation index for maintenance support of air defense missile equipment under the background of islands and reefs as an example， it is proved that this method can reduce the index system more scientifically and efficiently through comparative analysis.

Aiming at the current situation that the missile equipment maintenance support effectiveness system is complex and huge，the indexes are interrelated，the data information is difficult to obtain and easy to lose and distort，a method based on grey-improved two-tuple linguistic is proposed to evaluate the maintenance support effectiveness.The method uses the improved G1 method and the improved criteria importance though intercrieria correlation（CRITIC） method to obtain the subjective and objective weights respectively，and obtains the comprehensive weight according to the minimum information identification method.The grey clustering analysis method is used to transform the quantitative data into the binary semantic form，and the improved binary semantic is used to transform the qualitative language evaluation information and evaluate the complete system.The weight of each index obtained by is more scientific and reasonable，avoiding the loss and distortion of information，and the evaluation results are more accurate.The evaluation results of the model are basically consistent with the actual situation.It can truly and scientifically reflect the effectiveness level of missile equipment maintenance support and can find out the weak links in a targeted manner，which can provide a basis for the management and improvement of missile equipment maintenance support system.