Due to the exact demands of bipolar membrane electrodialysis (BMED) on water quality, an effective pretreatment for the effluents from desalination processes is one of the most important tasks for putting the bipolar membrane electrodialysis reclamation technology into practical use. In this study, an enhanced softening method in which the Na2CO3-NaOH softening and polyaluminium chloride coagulation were combined was attempted. Series of experiments designed by Response surface methodology (RSM) were conducted for exploring the relationships between the removal rate of the contaminants and the relevant independent variables. Based on the obtained models, an optimum scheme can be achieved. At last, various kinds of typical domestic cation exchange resins were attempted for further reduction of the hardness and the relevant optimum operating conditions, such as resin type and flow rate of brine, were obtained.