In order to reveal the performance of reverse osmosis applied in the radioactive wastewater treatment,treatment experiments are carried out on a pilot RO equipment using wastewater containing manganese nuclide.Results show that the rejection ratio of RO to manganese is almost not influenced by the operation pressure and the ration of reclaiming,and has no direct relation with the salt rejection ratio.The ratio of manganese rejection is more than 95% and can meet the requirement on the disposal of radioactive wastewater produced by pressurized water reactors.