The determination of competitive adsorption isotherm is of great importance for model-based design and optimization of chromatographic separation processes，especially for the simulated moving bed due to its intrinsic complexity.The competitive adsorption isotherms of ketoprofen enantiomers on an amylose-based chiral stationary phase(Chiralpak AD)at 25℃ were determined in this study by the application of the inverse method.Elution profiles of various racemic feed signals were measured on a preparative chromatography column with a precise temperature control system.The parameters of isotherm models were determined by fitting the experimental elution profiles.The mass balance for component in the column was described by equilibrium-dispersive model.In the fitting procedure，isotherm parameters were searched over a wide range in the parametric space with the non-dominated sorting genetic algorithm(NSGA-Ⅱ)and polished with the Levenberg-Marquardt algorithm.Four competitive adsorption isotherm models were compared based on the fitting to the experimental data.Bi-Langmuir model with 5 parameters gave the best results. In order to validate this model and the model parameters，independent overloaded profiles with different concentrations and amount of feed were measured and compared with the model. Quantitatively good agreement was observed.