A phenylalanine (Phe) imprinted polymer was prepared by the wet phase inversion method to investigate the optimum preparation condition which endows the polymer matrix with prominent adsorption selectivity. The addition of a large amount of porogen (dimethyl sulfoxide: DMSO) was needed to form macrovoids in the polymer matrix. For the high adsorption selectivity of the polymer matrix, a complex between functional monomers and a template molecule must be formed before the copolymerization of acrylonitrile (AN: crosslinker) and acrylic acid (AA: functional monomer). The formation of a phenyl group in the polymer matrix by the coupling reaction between DPhe and AA seemed to cause the reverse adsorption selectivity of the polymer matrix. The adsorption selectivity of the Phe imprinted polymer was dependent on the pH of the racemate solution. The adsorption selectivity of the D-Phe imprinted polymer prepared by the post implanting method reached 11 at pH 2 and showed a reverse adsorption selectivity at pH 4 and 6.