Abstract: Sunflower seed oil was extracted using supercritical carbon dioxide in a semi-continuous flow extractor with the temperature range 313-343 K and the pressure range 20-40 MPa. The extraction rates increased with pressure at each temperature, but decreased with temperature increase up to about 28 MPa. After this pressure, higher temperature favored the extraction rate because of the competitive effects of solvent density change and solute vapor pressure change with the variation of temperature and pressure, resulting the crossover effect of solubility of oil in supercritical carbon dioxide. The fatty acids composition of the extracted oil was similar to that of soybean and tomato seed oil with high content of oleic acid.