A new type of copper(II) metal complex containing 1,10-phenanthroline (phen) and 8-(difluoromethoxy)-3,4-dihydro-2H-[1,3]thiazino[3,2-a]benzimidazole (dtb) ligands was prepared and characterized. The ds-DNA interaction of the complex was studied by UV-Vis spectrophotometry, competitive fluorometric titration with ethidium bromide (EB) and 4',6-diamidino-2-phenylindole (DAPI), viscosity measurements and agarose gel electrophoresis. The results show that the complex can bind to ds-DNA in the minor groove by displacing DAPI molecules. DNA cleavage mechanism studies revealed that hydrogen peroxide radicals are responsible for DNA oxidative cleavage.