Abstract: Complexation enhanced adsorption process was put forward to purify radioactive wastewater in nuclear power plant. EDTA was selected as the complexant, activated carbon (AC) as the adsorbent and cobalt as the target nuclide to observe the feasibility of this process and the impact of related factors. The results show that the removal rate after adsorption by AC improves remarkably by adding EDTA into the solution, which fits the theoretical expectation well and verifies the feasibility of this process. The results of conditional experiments show that the removal rate increases with the amount of AC, the adsorption equilibrium time is 16 h, the pH of the solution influences the processes of complexation and adsorption significantly, and the most suitable pH is about 7.0, and the highest removal rate is obtained with the molar concentration ratio of EDTA to Co²⁺ of 1∶1. The adsorption properties of AC for EDTA-Co complex were investigated by data fitting. The results show that the adsorption fits Freundlich isotherm model well, and the kinetic process of adsorption can be described by the pseudo-second-order kinetic model.