A direct selective oxidation of methane to a methanol derivative with the catalysis of palladium acetate/benzoquinone/molybdovanado-phosphoric acid using molecular oxygen in trifluoroacetic acid has been suggested. Methyl trifluoroacetate is the only liquid product, and its highest yield could be obtained at 80-100 degrees C. The addition of perfluorooctane could improve the yield of methyl trifluoroacetate significantly. The reaction product can be easily separated from the reaction system, using the difference of boiling points.