Abstract: The appearance of puerarin crystals that formed in three kinds of solvents(acetic acid-ethanol, ethanol-water, isopropanol) in the electromagnetical field were observed by using SEM, and the purity of crystals was detected by high performance liquid chromatography(HPLC). Results show that the crystallization velocity is remarkably enhanced and the purity of puerarin crystals is improved in electromagnetic field with the intense of 0.24T. The purity of puerarin crystals is up to 99.5% in the solvent of isopropanol. Moreover, uniform crystals in order can be obtained in the same solvent.