On extraction of refined oil from citrus peel by supercritical CO_2 fluid,the influence law of several parameters on extraction rate of refined oil were studied,which include particle size,material mass,extracting pressure,extracting temperature,extracting time and separating temperature.Based on sense evaluation of refined oil and dissolving experiment,the main components of refined oil were obtained.It is demonstrated that expanded polystyrene plastics can be weel processed with refined oil.