The previous investigations showed that pine bark contains flavanolignan and dihydroflavanol compounds that have interesting and important therapeutic activities. One of this compounds is taxifolin. The bioflavonoid taxifolinithe most promising natural antioxidant. The antioxidative activity oftaxifolin exceeds that most common antioxidants such atocopherols (vitamiE) and carotenoids (vitamin A).An important advantage of taxifolin is the ability to preventcancers. Taxifolin is also a very important nutrient for blood. ThisFlavonoid improves blood circulation and reduces blood levels of low-density lipoprotein (LDL) cholesterol. Extraction of antioxidants from plant with toxic liquid solvents under specific conditions, such as high temperature, acid and enzyme contact, significantly decrease the biological quality of the natural medicinal materials. The extraction method must be designed in such a way that extracted compounds do not contact the toxic and carcinogenic solvents. In this study, it is focused on the experimental production of taxifolin via supercritical fluid extraction method and characterization of the produced toxifolin. Extraction experiments were performed using pine bark powder, supercritical carbon dioxide and ethanol. For separation of taxifolin from pine bark, supercritical CO 2 extraction was carried out on a laboratory scale under the following operating conditions: 40-60?C; 10-30 MPa; 0.4-2 ml/min CO 2 flow rate; 30-150 min (extraction dynamic time). High performance liquid chromatography(HPLC) was applied to identify taxifolin in extracted samples. In order to obtain maximum taxifolin recovery as the objective function of this research, the effective extraction parameters were optimized using response surface methodology. The optimum conditions were found to be the extraction dynamic time of 133.03 min, 18.48 Mpa, 41.01?C and 1.72 ml/min to achieve taxifolin recovery of 34.15%. Response surface analysis showed that the data were adequately fitted to second-order polynomial model.R 2 and modified R 2 of the model are 98.27% and 96.76%, respectively.A general mathematical model for supercritical CO 2 extraction was performed.The model was developed utilizing diffusion-controlled regime in the pore and film mass transfer resistances with axial dispersion of the mobile phase at dynamic conditions. The mass transfer parameters, i.e., effective pore diffusivity, film mass transfer coefficient and axial dispersion, along with the Henry coefficient were chosen as the model parameters. The first three mass transfer parameters were predicted using nondimensional equations from the literature. Henry law was used to describe the equilibrium state of solid and pore fluid phases. Genetic algorithm was applied to determine the optimal value of Henry coefficient such that to minimize the absolute average deviations between the experimental and predicted extraction recoveries. Indicated by obtained results, the mathematical model is able to predict the experimental data with acceptable accuracy.The main process conditions which must be determined to maximize the extraction recovery are temperature, pressure, flow rate of CO 2 , and dynamic extraction time. These were optimized by genetic algorithm. The optimal operating conditions were observed at 40?C, 18.57 MPa, 1.98 ml/min, and 132.21 min. There was good agreement between two methods of optimization.Supercritical fluid extraction by carbon dioxide as extraction solvent have lots of advantages such as low supercritical temperature and non-toxicity. Keywords Pine bark, Taxifolin, Supercritical extraction, Response surface methodology, Optimization,Mathematical modeling.