Abstract: Orange peel oil was extracted by supercritical fluid-CO2 (SCF-CO2) and its constituents were analyzed by GC-MS. The effects of extraction time, pressure, temperature, CO2 flow rateand separate temperature on the oil yield were studied. The optimal conditions were determined by orthogonal experiments. The optimal conditions were as follows: extraction time 60 min, extraction pressure 20 MPa, extraction temperature 40 ℃, separation temperature 50 ℃. At the conditions, the oil yield was 0.86%. GC-MS analysis revealed that the main constituent of the oil was 5,5'-dimethoxy-3,3'-dimethy-2,2'-bina-phthalene-1,1',4,4'-tetrone which amounted to 35.54%, and the other main constituent was β-hydroxy-methyl-norethisterone-methyl-oxime which amounted to 24.60 %.