The nuclear heating reactor (NHR) is designed with a number of advanced and innovative features, including integrated arrangement, natural circulation, self-pressured performance, hydraulic control rod drive and a passive safety system. The engineering project feasibility of 200 MW(t) nuclear heating reactor (NHR200) for the district heating in many northern cities of China has always been carried out by INET since the prototype NHR5 was constructed in 1989. The redesign of 2x200 MW(t) nuclear heating reactor (double NHR200) as a heat source heating to a site in Shenyang city, Liaoning province, has been finished recently. This paper presents an economic feasibility analysis of 2x200 MW nuclear heating reactor for seawater desalination by multi-effect distillation (MED) with a 320,000 m(3)/d freshwater production plant in an assumed site in the coastal area of north Africa, which total capital investment cost for double NHR200 was adjusted based on those of original NHR200 seawater desalination plant under its structure redesign. The result indicated that the levelized discounted production of water cost is $0.87/m(3), which is lower than that of NHR200 seawater desalination plant. Four sensitive factors for the cost of water desalination were analyzed and compared. The discount/interest rate is one of the factors that have the greatest effect on the water cost. Its water cost is $0.71/m(3) while the discount/interest rate is 5%, which can bear the economical comparison with a usual coal-fired or oil-fired seawater desalination plant. Therefore, The double NHR200 seawater desalination system provides a very attractive economically solution to satisfy the demand of seawater desalination energy without contributing to increasing environmental pollution and greenhouse gas emissions. The other factors that have effect on the water cost are purchased electricity cost, capital investment and fossil fuel price respectively.