The polystyrene supported phenylalanine Schiff base complex of Mn(II) (PS-Sal-Phe-Mn) was prepared with chloromethylated styrene polymer beads, 2,4-dihydroxybenzaldehyde, L-phenylalanine and manganese (II) acetate tetrahyrate., The polymeric ligand and the complex were characterized by FT-IR,, small area X-ray photoelectron spectroscopy (XPS), and ICP-AES. In the presence of the manganese complex, cyclohexene (1) was effectively oxidized by molecular oxygen without reductant. The major products of the reaction were 2-cyclohexen-1-ol (2), 2-cyclohexen-1-one (3) and 2-cyclohexen-1- hydroperoxide (4), which was different with typical oxidation of cyclohexene. The influence of reaction temperature and additive for oxidation had been studied. The selectivity of 2-cyclohexen-1-hydroperoxide varied with reaction time and different additives. The mechanism of cyclohexene oxidation had also been discussed. The polystyrene supported phenylalanine Schiff base complex of Mn (II) (PS-Sal-Phe-Mn) was prepared with chloromethylated styrene polymer beads, 2,4-dihydroxybenzaldehyde, L- phenylalanine and manganese (II) acetate tetrahyrate. and the complex were characterized by FT-IR ,, small area X-ray photoelectron spectroscopy (XPS), and ICP-AES. In the presence of the manganese complex, cyclohexene (1) was effectively oxidized by molecular oxygen without reductant. The major products of the reaction were 2-cyclohexen-1-ol (2), 2-cyclohexen-1-one (3) and 2-cyclohexen- 1-hydroperoxide (4), which was different with typical oxidation of cyclohexene. The influence of The selectivity of 2-cyclohexen-1-hydroperoxide varied with reaction time and different additives. The mechanism of cyclohexene oxidation had also been discussed.