Rosa damascene which grows in most parts of Iran is a source of Flavonoid andantioxidant compounds like Quercetin and Kaempferol,which are widely used in medical and sanitary industries .Quercetin is a polarpolyphenolic compound which is used in illness treatment like Artery stenosis, Cataracts, Dypertension, Diabetes and Colon Cancer. The common technique to extract plant ingredients is the conventional method such as Soxhlet with organic solvents such as ethanol and methanol. But for pharmaceutical and medicinal applictions, a suitable method for extraction and purification without utilization of toxic organic solvents is needed.Supercritical fluid extraction especiallysupercritical carbon dioxide extraction as an efficient extraction method has attracted attention during the last decades, as its advantages include beingnon-explosive, non-toxic, and available in high purity with low cost, non-solvent residues. In this study, organic solvent extraction method and supercritical carbon dioxide extraction of Rosa damascena was compared.The extraction of Quercetin was investigated by modified supercritical CO 2 with constant volume ofco-solvent (1 ml), 20 min of static time and 0.674 mm of average particle size. Design of experiment carried out with response surface methodology (RSM) using Minitab software.Supercritical CO 2 extractionwas carried out under the following operating conditions: 35-55°C; 10-30 MPa; 0.3-1.5 ml/min (CO 2 flow rate); 40-120 min (extraction dynamic time). Response surface analysis verifiedthat the data were adequately fitted to second-order polynomial model and the statistical analysis also showed that the linear and quadratic terms of pressure,temperature, CO 2 flow rate and extraction dynamic time, as well as the interactions of pressure and temperature, and temperature and flow rate, have considerable effects on the proposed model of Quercetin recovery based on coded variables. R 2 and modified R 2 of the model are 92.99% and 86.86%, respectively.It was predicted that the optimum extraction conditions within the experimental ranges would be the extraction pressure of 25.55 MPaand temperature of 45.7 o C with flow rate of 0.81 ml/minand extraction time of 108.68 min. Under such conditions, the recovery of Quercetin was predicted to be 31.75%.Moreover, in this work, a mathematical modeling for Quercetin extraction from Rosa damascena was performed by modified supercritical carbon dioxide based on the differential mass balance. Density and viscosity of dense gases mixture was obtained by Peng-Robion (PR) equation of state with the van der Waals mixing rules and Chung et al., respectively. Mathematical model parameters are effective pore diffusivity, film mass transfer coefficient, axial dispersion, and distribution coefficient. The first three parameters were obtained from empirical equations and the distribution coefficient between solid and solvent has been determined by thermodynamic modeling of solubilities.Finally operating conditions were optimized by means of Genetics Algorithm method in Matlab. By this method optimal operating conditions were observed at 42.56 ?C, 25.62 MPa, 1.158 ml/minand 101.66 min (dynamic time) to achieve 31.72% recovery. The experiments from RSM corresponded to GA results well. Keywords Rosa damascena ;Quercetin; Supercritical CO 2 extraction; Response surface methodology; Genetic algorithm; Mathematical modeling.