Abstract: The diatomite filter + two-stage reverse osmosis membrane + ions exchange system in the application of radioactive waste treatment were studied by 200 L/h pilot system. The remove efficiencies for radioactivity and conductivity were mainly studied, and the removal efficiencies of different inlet water were compared. The experimental results show that the removal efficiency of radioactivity for the first and second stage RO membrane is 95%-98% and the removal efficiency of radioactivity for the two stage RO membrane is higher than 99.9%. Experimental results also show that the outlet through the system is lower than 1.1 Bq/L for wastewater with radioactivity of 32 290 Bq/L.