Abstract:(RO) system in the zero discharge process of high salinity coal mine water, the multi-stage reverse os⁃mosis(RO) system was optimized based on computational fluid dynamics(CFD) simulation. An optimi⁃zation scheme was proposed regarding the arrangement and combination of membrane elements in two-stage membrane concentration unit. Technical analysis and economic analysis were carried out. The re⁃sults show that, after optimization, the distribution of ion pollution in the membrane element and thedosage of scale inhibitors remain the same. Six membrane elements are reduced in each of the primarymembrane concentration unit and secondary membrane concentration unit, which accounting for approx⁃imately 5% of the whole membranes elements of the multi-stage reverse osmosis(RO) system. The totalinitial investment of membrane elements is saved by 48 000 yuan. The recovery rate of coal mine waterincreases from 96.5% to 97%. The power cost rises by 0.017 yuan/m3, while the evaporation and crys⁃tallization cost is reduced by 0.395 yuan/m3. Therefore, the total operation cost is saved by 0.379yuan/m3. Close-