Polypropylene films with various amine groups were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) films and the subsequent amination of poly-GMA graft chains were examined. The physical and chemical properties of the GMA-grafted PP film and the aminated PP film were investigated by IR, SEM, XPS, and TGA. The adsorption of urokinase for the PP films modified with various amine groups was examined under various conditions of different amine group contents and pH values. The adsorption of urokinase increased by increasing the amine group content. In the range of amine group content from 1.0 to 2.7 mmol/g, the adsorption of urokinase by the PP films modified with six kinds of amines was in the following order: trimethylamine > diethylenetriamine > triethylenetetraamine > ethylenediamine > dimethylamine > diethyleneamine. The adsorption amounts of urokinase by the PP film with the trimethylamine and triethylenetetraamine groups at pH 7.4 were higher than those at pH 9.