The feasibility study of nuclear seawater desalination demonstration plant has been finished recently by Institute of nuclear and new energy technology,Tsinghua University,which including two desalination technology options coupled to a 200MW low temperature nuclear heating reactor (NHR).One is the desalination system using low temperature (＜70℃) multi-effects distillation process with horizontal tube bundle arrangement with a thermal vapor compression (MED-TVC) couple to a 200MW NHR production 120,000 m3/d -Case-1.Other one is the desalination system using high temperature (＞70℃&＜120℃) MED with vertical tube evaporators (VTE-MED) couple to a 200MW NHR with 160,000 m3/d-Case-2.The results of their economic feasibility study indicate their significant economics in the large scale MED plants.Of course,the economic assessment indexes of Case 2 is better than that of Case 1,which including project total investment cost,specific construction cost,net present value,internal revenue rate,annual total product cost and average unit production cost in economic lifetime,etc..