A life cycle assessment was conducted to study the environment impact of a desalination plant with reverse osmosis and low temperature-multiple effect distillation as major technologies from its infrastructure construction to operation. The results showed that two processes of reverse osmosis and low temperature-multiple effect distillation had the maximum environmental load in the desalination treatment stage,accounting for 70% and 60% of the total,respectively. In addition,they made great contribution to environmental indexes such as acidification potential,marine aquatic ecotoxicity,global warming potential and photochemical oxidation. Low temperature-multiple effect distillation technology had a lower influence on abiotic resource depletion whose impact factor was chemical agent input and ozone layer loss indexes than reverse osmosis,but its contribution value was larger than reverse osmosis for other environmental indexes. In general,energy consumption was the major impact factor for high environmental load of desalination process,and reverse osmosis would be the development trend of desalination due to its lower energy consumption,higher effluent quality,smaller space occupation and higher efficiency in the future.