Through the reaction of 4,5-diiodophthalonitrile with perfluorohexyl iodide, 4,5-di(perfluorohexyl)phthalonitrile was obtained, then 2,3,9,10,16,17,23,24 –octa (perfluorohexyl) cobaltphthalocyanine was synthesised. The products were characterized by 1H NMR, 19F NMR, MS, IR. Target product were characterized by HRMS,IR and UV-vis. It was used to catalysis the reaction of oxidation of ethyl benzene in fluorous biphase system. The results showed that: the conversion of ethyl benzene was up to 41.8% and the selection of acetophenone was 85.3% under the conditions of perfluorooctane as solvent, the molecular oxygen as oxidant, the amount of catalyst was 0.03 mmol, the reaction was carried out at 120℃ for 6 h. Fluorous biphase system can be repeatedly used five times without lossing its catalytic.