According to the process and site conditions of the Yongcheng Kaikong reuse mine water project, it was suggested to control the hardness, regulate pH, select the reasonable rate of recovery and optimize the choice of antiscalant after theoretical analysis, calculation and experimental study. The optimal conditions for a safe and economical reverse osmosis system were calcium concentration lower than 160 mg/L, pH equal to 7.4, antiscalant dosage 2.8?10?6(?). The results of three-year running showed that the scaling problem has been effective controled, and the pressure difference and the desalination rate have undergone little change.