: Nowadays, according to growing of industries and increasing competence among managerial organizations and manufacturing companies, improving quality and longing lifetime of products and manufactured parts has become a main concern of experts and those who are involved in these issues. In this research, we addressed improving reliability of systems. Reliability is investigated in some steps. First of all, the step of machine or considered system designing, production or accomplishing step after that post-production step in which life estimation and analyzing affairs related to guarantee and warranty are done. Problem dealt with in this dissertation is improving reliability in designing and pre-production steps. Proposed solution is formed based on evaluating drawbacks of previous researches and by focusing on this fact that prominent structure for production should be applicable in real world. Feasible structures for system are designed and assessed then the appropriate one for production is picked up. The proposed method for selection of the superior alternative(s) is to determine effective criteria based on conditions of each problem and then applying Analytic Network Process (ANP) as a highly applicable and robust technique in multi criteria decision making problems, since it takes relations among all effective components into account. Results demonstrate that determining criteria and their value against each other is important thus the problem should be considered by experts. Moreover, results show that if the used method for determining ranking of alternatives is changed, it may also lead to changes in the final result, so more attention should be paid to choose the selection method. Keywords: Reliability; Multi Criteria Decision Making (MCDM); Analytic Network Process (ANP);