Forward osmosis(FO) is a concentration on the nature phenomena of osmosis. It is nowadays considered a breakthrough technology that can be potentially used for concentrating solutions and suspensions. The diluted nature of brine restricts the treatment technologies that can be applied. Then, brine concentration by FO could represent a habilitating technology enabling the application of a wider range of treatment alternatives. The performance of concentrated brine depended upon FO membranes was investigated at normal temperature and pressure in this research. Cellulose triacetate on radio-frequency-weldable nonwoven support (CTA-NW) and a thin-film composite with embeded polyester screen support (TFC-ES) were compared; and their orientations were consisdered. The brine was from Chaerhan saltlake after extracting potassium as feed solution, NaCl solution or MgCl2 solution as draw solution. The results indicated that CTA-NW exhibited better concentrate performance than TFC-ES; while the water fluxes of the two membrane was exactly opposite. In case of CTA-NW in AL-FS(active layer facing feed solution) orientation with MgCl2 as draw solution, the concentration factors of Li+ was nearly 3.0. Quantitative structure-activity relationship (QSAR) of FO membranes and concentration characteristics was correlated, based on results of SEM, FT-IR, and contact angles studies. The concentration performance could be mainly attributed to the porosity and the thickness of FO membranes; while the water flux was depended on hydrophily of FO membrane surface.