In recent years, the importance and requirements for high-quality energy and water has been increased significantly, and this trend will strongly continue. One of the promising solution for the water scarcity's problem is desalination of the oceans salt water by thermal methods, and if the required thermal energy is provided by wastes of a thermal power plant it will be competitive with other methods. In this paper, a combined cycle including solid oxide fuel cell (SOFC) and gas turbine is used as thermal resource. Here, combination of these two systems beside of multi effect desalination (MED) system leads to reduce in energy consumption, pollutant emissions, investment and operation and maintenance cost, as well as increase of efficiency in comparison with the conventional individual systems. Exergetic and economic analysis using a computer program in EES software was performed. The results proposed a system with thermal and exergy efficiency of 60 % and 57%, respectively. The system expenditures and revenues were estimated, and the effect of two important design parameters, i.e. operational temperature and current density of fuel cell, on exergy efficiency and levelized cost of electricity were investigated. Consequently, the reliability and availability of the proposed system are calculated as 0.842, using the Markov method. It is seen after reliability analysis and availability calculation the exergy and energy efficiency is reduced and LCOE increased by 8.8%.