Abstarct: Abstract One of the most important pollutants in all industrial activities, including power plants, is industrial wastewater, which must be controlled fundamentally in order to prevent its harmful effects and save the country's limited water resources. Due to the high energy consumption of different desalination systems to produce fresh water, as well as the heat losses in power plants, a major part of the wastewater produced in power plants can be desalinated for reuse in processes that require water. Desalination system with steam ejector (MED-TVC) is one of the most efficient methods that is widely used in water desalination. In this research, the MED-TVC desalination system with parallel/cross flow in combination with Iranshahr steam power plant has been modeled in order to use the existing heat loss for the desalination of the existing wastewater. Considering the low flow rate of the effluent flow of Unit 10 and the cooling tower of the power plant, a new arrangement for the flows of the MED-TVC desalination system is proposed. Technical and economic modeling and evaluation have been coded in MATLAB software and the sensitivity analysis of various operational parameters such as the number of effects, the temperature of the driving steam and the concentration of the outlet brine have been studied. At first, the system modeling is done by mixing the two streams of unit 10 and the cooling tower of the power plant as input feed to the system, due to the low salt concentration of the resulting feed (about 1170ppm), its sweetening by the MED-TVC system is not common. For this reason, the modeling of the proposed system with the new arrangement of flows (unit 10 effluent as input feed to the system and cooling tower effluent as input to the system condenser) is investigated. The modeling results show that the use of a water desalination unit with 4 effects is capable of producing 63 m3 of fresh water and consuming about 9 m3 of waste steam per day with a performance ratio of 7.1. Also, the cost of produced fresh water and the total investment cost are respectively equal to It is 1.45 $/m3 and 232470 $.