Aiming at cold-pressed oil cakes of linseed and sunflower seed, the pore fractal characteristics of microstructures have been studied. By combining Hagen-Poiseuille equation with fractal theory, a fractal permeability model for oil cake has been developed. The permeability of linseed and sunflower seed cakes under cold-pressed condition has been measured. It was found that the relative average errors are 12.8% and 16.8% for the soybean cake and sunflower seed cake respectively by com...