Objective: The dynamic mathematical model of ultrasonic extraction of polyphenols from pomegranate peel was constructed with the Fick' s second law as the theoretical basis. Methods: The spherical model was selected,with mass concentrations of pomegranate peel polyphenols as the index,50% ethanol as the extraction solvent and ultrasonic extraction as the extraction method. In different test conditions including the liquid ratio,extraction temperature and extraction time,a series of kinetic parameters were s...