Desalination processes make freshwater from the separation of salt from seawater or brackish water. Seawater (about 97.5% of the total available water), in abundance, constitutes a reliable sustainable source of freshwater, with high potential to fulfil the continuously increasing freshwater demand of the future [1]. Today, main types of desalination processes are used worldwide, Multiple Effect Distillation (MED) and Multi Stage Flash (MSF), Reverse Osmosis (RO) and Electro Dialyses for this porous [2]. Reverse Osmosis is the most widely adopted. It achieves the separation of freshwater through the use of a semi-permeable membrane which allows the passage of water whilst preventing the passage of salts into the permeate stream. Recently Ashkelon seawater reverse osmosis (SWRO) Plant is now featured as a successful model in this filed [3]. The chabahar maritime university desalination plant which its prototype was launched in 1994, currently with two set reverse osmosis membranes (recovery ratio of 50%) is producing fresh water with a capacity of 432±20 m3/h with TDS of 500±50. In the present work, it is attempting to draw the unit design and to product technical documents of its constituent parts. Also process specifications such as feed water quality and quantity, the amount and quality of the outlet water, pre-preparation and post-preparation processes, etc. are investigated and recorded. Finally, while estimating cost and technical analysis of the process, the strengths and weaknesses of the RO system are compared with the updated RO system, we will have suggestions for increasing the efficiency and quality of producing freshwater. The results indicate that intake seawater with TDS of 28000-34000 is of variable quality and inadequate quantity. The site requires structural and technical improvements to keep up-to-date and work by high efficiency. For post treatment, adding some important minerals, especially magnesium and calcium, is recommended for drinking purposes. And like most plant, sometimes the water consumption increases than the amount of site production. This causes tension in the work of the site, especially the reverse osmosis membrane modules.