In this paper, for purification of eutrophic Lake Water, immobilized nitrobacteria-denitrifying bacteria made from radiation copolymerization at low temperatures by means of glass forming monomers, i.e.2-hydroxyethyl acrylate (HEA) and polyethylene glycol dimethacrylate (14G) have been used-The Sequencing Batch Reactors (SBR) system and cell proliferation of nitrobacteiia-denitiifying bacteria techniques were carried out in order to treat eutrophic lake water.The results showed that the removal efficiencies of immobilized nitrobacteiia-denitiifying bacteria for Total N (TN), NH₄⁺-N and COD_cr were 70%, 84% and 68%, respectively.The results demonstrated that the optimum temperature of immobilized nitrobacteria-denitrifying bacteria system was 28℃.Immobilized nitrobacteria-denitrifying bacteria was more resistance to low temperature(10℃).The dissolved oxygen (DO) concentration have effect on removal efficiencies for Total N(TN).