A method for preparing a biflavone-iron complex, includes using the amentoflavone as the ligand and the ferric ion as the central ion, the amentoflavone-iron complex is obtained by reaction, and the structure of the complex is characterized by infrared spectroscopy, UV-vis absorption spectroscopy and high resolution mass spectrometry. Meanwhile, the antitumor and antioxidant activities of the amentoflavone-iron complex are studied in the present invention. MTT method shows that the amentoflavone-iron complex has a relatively good antitumor activity, and the antitumor activity thereof is stronger than that of the amentoflavone. Pyrogallol auto-oxidation method and ABTS method show that the antioxidative activity of the amentoflavone-iron complex is stronger than that of the amentoflavone itself.