Selective cation-exchange membranes are placing a key role in separation processes. The application of selective cation-exchange membranes is wide since there are many kinds of mixtures needed to be separated for reuse. In this study, a facile and efficient one-pot approach was used to obtain monodispersed methyl methacrylate-N-isopropyl acrylamide (MMA-NIPAm) polymer by atom transfer radical precipitation polymerization (ATRPP) and then MMA-NIPAm chiral selective separation membranes were prepared for separating racemic equol. Firstly, using dodecylbenzenesulfonyl chloride (DBSC) as the initiator, bipyridine (bipy)/CuCl as the catalyst system, acetonitrile as the solvent, and S-equol as template molecule by which a MMA-NIPAm copolymer was synthesized and it was characterized by TEM, FTIR, TGA, UV-vis absorption spectrum, and dynamic layer scattering analysis. Lastly, MMA-NIPAm chiral separation membranes were prepared by casting 3 wt% of MMA-NIPAm copolymer dimethyl formamide (DMF) solution on a rimmed glass plate and evaporated the solvent completely at 100 °C under vacuum. Then, the PMMA-PNIPAm chiral selective cation-exchange membranes were prepared by immersing in methanol/acetic acid (95:5, v/v) to remove the template molecules. Most worthy of mention was that the prepared chiral selective separation membranes could separate S-equol and R-equol from the mixture of racemic equol. In application of a thermo-responsive monomer, the separation ability of the prepared PMMA-PNIPAm chiral separation membranes could be tunable according to environment temperature changes.