The security of reverse osmosis combined with a pretreatment process of disc filtration-ultrafiltration to treat the radioactive wastewater was analyzed and evaluated.Several aspects including reliability and security during operation,maintenance and decommissioning were investigated in this paper.Results showed that safe operation can be ensured by rational process design and scientific management.Estimation on radiation safety showed that the absorbed dose rate is below 0.04 mSv/h on the surface of reverse osmosis module,which can ensure the radiation safety of operators.