In this paper a two- phase method is applied for maintenance strategy selection problem. As selecting the most appropriate maintenance strategy requires different alternatives to be assessed for a range of criteria, it could be assumed as a typical multi- criteria decision making problem. There also exist several key factors affecting the selection procedure such as reliability, services quality, risk, etc., which taking all of these factors into account make the decision makers encounter with a huge amount of data that might be accounted as redundancy. In the first stage of the proposed methodology, Factor Analysis (FA) technique is applied to extract the covert structure between different criteria and provide a coherent set of variables by means of clustering. In the second phase, a fuzzy TOPSIS method is presented to deal with the uncertain and imprecise judgments of decision makers which would be translated into fuzzy numbers. In addition, a numerical example is presented to accredit the validity of the proposed model.