Optimal extraction conditions such as pressures, temperatures, and modifiers on glycyrrhizin extraction from licorice were investigated using supercritical $CO_2;(SC-CO_2)$ at 3 mL/min flow rate. Morphology of licorice tissue, after glycyrrhizin extraction, was examined by SEM, and absolute density ($g/cm^3$) measurement and glycyrrhizin content were determined by HPLC. Pure $SC-CO_2$ had no effect on glycyrrhizin extraction, but recovery of glycyrrhizin ($32.66{pm}0.77%$) was enhanced when water was used as modifier. The highest recovery was $97.22{pm}2.17%$ when 70% (v/v) aqueous methanol was added to 15% (v/v) $SC-CO_2$ at 50 MPa and $60^{circ}C$. Under optimal extraction conditions, 30 MPa pressure and $60^{circ}C$ heating temperature, glycyrrhizin recovery reached maximum ($102.67{pm}1.13%$) within 60 min. Licorice tissue was severely damaged by excessive swelling, and absolute density of licorice residues was highest when aqueous methanol was used as a modifier.