A new complex [Cu (Thr)(Phen)H2O] SO4 . HO2 x CH3 OH (Thr = DL-Threonine, Phen = o-Phenanthroline), which has not been published, was synthesized and characterized by elemental analysis, IR spectroscopy, and TG-DTA. The interaction of the complex and sperm DNA was studied by electronic absorption and ethidium bromide (EB) fluorescence spectroscopy. The result indicates that the maximal absorption peaks of this complex are red-shifted and the intensity is weakened; At the same time, it can to some extent quench the emission intensity of EB-DNA system. Therefore, the authors come to a conclusion that the interaction of this complex and sperm DNA is intercalation.