Abstract: According to the characteristics of radionuclide exists in the low-level radioactive reactor waste water from HFETR, we use a new combined membrane process separation technology to study the efficient treating of low-lever radioactive reactor wastewater. First, the prepared the simulated wastewater contained Cs+, Sr²⁺, Co²⁺, Ni²⁺, and Fe³⁺. Then, we sequentially investigated the pressure, ion concentration, pH value and EDTA, which have effects on the desalination rate of membrane processing metal ions in wastewater. The results show that: in the condition of pH = 7, and added 0.15mol/L EDTA, the simulated wastewater separated by UF-RO, desalination rates of Cs+, Sr²⁺, Co²⁺, Ni²⁺and Fe³⁺are all above 95%; In the subsequent trials, adding 0.15mol/L EDTA into the radioactive residuary solution, and then treating by UF-RO-RO, the decontamination efficiency can reach 95.7%.