Abstract: Flocculation as an enhanced treatment process was put forward to remove corrosion products in liquid radwaste from nuclear power plant (NPP). It is found that the prepared colloidal solution can simulate source terms of corrosion product in NPP through qualitative and quantitative analysis of water samples. Experiments of flocculant selection (polymer and inorganic salt) were done focusing on colloidal particle size distribution (200-300 nm) and content features (influenced by pH). Results indicate that both polymer B and B+inorganic salt Y show better purification effect via flocculating (effluent met engineering requirements of DF>50) and flocculant B is recommended in subsequent engineering design considering of removal efficiency (flocculation reaction time) of colloids.