Extraction of egg yolk oil (EYO) from egg yolk powder with supercritical carbon dioxide(SC-CO 2) was performed at 45 ℃ and 32.0 MPa in a 1.2 L laboratory apparatus. The effects of particle size and flow rate of CO 2 on the extraction were investigated. The controlling steps in extraction were external diffusion of EYO and equilibrium of EYO between SC-CO 2 and matrix. A mathematical model was developed for simulating the extraction process . The model could simulate satisfactorily the process of extraction of EYO with SC-CO 2. The volumetric mass transfer coefficient K f a was directly proportional to the flow rate of CO 2 with an exponent of 0.548