Reverse osmosis device is sufficient pressure to the solution of the solvent (usually water) through the reverse osmosis membrane and separated, this process and the natural infiltration of the opposite direction, so called reverse osmosis. After reverse osmosis treatment, so that the content of impurities in the water lower and improve the purity of the water, the desalination rate of 99% or more, and most of the water can be bacteria, colloids and large molecular weight organic removal. Reverse osmosis can adapt to all kinds of salt content of raw water, especially in the high salt content of water treatment works, this desalination water treatment process can get a good technical and economic benefits.