Abstract: The supercritical CO2 fluid was applied in extracting oil from cucumber seed.The effects of extraction pressure,temperature,time and CO2 flow on the oil extraction efficiency were investigated by orthogonal experiments.The fatty acid composition of cucumber seed oil was analyzed by GC-MS.The results showed that the significance of the effects of these factors on the oil extraction efficiency were in the order of: extraction pressure,temperature,time and CO2 flow.The maximum extraction efficiency of cucumber seed oil could reach to 26% under the extraction pressure of 35MPa,35℃,for 120min at CO2 flow 45L/min.The cucumber seed oil has four fatty acids,the linoleic acid content is up to 77.81%.