Seawater desalination for low temperature nuclear heat reactor (NHR) has been studied for many years in China and other countries in the world, such as Morocco, and five countries in North Africa. Now, the feasibility studies of nuclear desalination demonstration plants are being performed using NHR with 200 MW thermal coupling to a multi-effect distillation (MED) plant, with a production of 160,000 m(3)/d (NHR-200) in Yintai City, Shandong province and Tianjin City on the coastal area in eastern China. This paper presents the economic assessment of the NHR-200 in Tianjin City, and reviews the economics of the different power sizes of NHR coupling to the MED, e.g. NHR-10, NHR-200, double NHR-200 in North Africa, the Middle East, the Red Sea and the Arabian Gulf It is very suitable to satisfy the site of no great electric grid, drought and scarce of freshwater for the characteristics of NHR with safe, clean and low total investment.