the effects of various parameters of supercritical carbondioxide(SC-CO2) fluid extractions of tomato peel by-product containing tomato seed and antioxidant activities of lycopene-rich extracts were investigated. The effect of three independent variables by extraction at temperature of 40 -100 C,pressures of 20-40 MPa, a particle size of 1.05 mm and flow rates of 1-4 mL/min. Oil from tomato seed was extracted under similar operating conditions and analyzed using GC-MS and GC-FID, while carotenoids extracted were analyzed by HPLC. The optimum operating condition to extract lycopene, under which 56% of lycopene extracted, was found to be 90 C ,40 MPa. In another experiment , The maximum total lycopene content of 31.25 μg/g of raw tomato was extracted at the highest temperature of 100 °C, 40 MPa by TEAC assay. TEAC assay was applied to assess the antioxidant activity of lycopene-rich extracts from SC-CO2 fluid extraction. The effects of SC-CO2 fluid extraction parameters on the antioxidant activities of the extracts differed with the yield. Temperature, pressure, and the quadratic term for the temperature of SC-CO2 extraction were large significantly positive factors affecting lycopene yield .For each unit of lycopene extract, the antioxidant activity level was constant below 70 °C, but then gradually decreased above 70 °C due to isomerization occurring as a result of the higher temperature. The ratio of all-trans-lycopene to the cis-isomers changed decreased. No significant effects of pressure or flow rate of SC-CO2 fluid extraction on the antioxidant activity were observed.