Psoralen is used in the treatment of vitiligo and angelicin(isopsoralen) is a photosensitizing agent. A reversed-phase high performance chromatographic method was developed to determine the contents of psoralen and angelicin from Psoraleae Semen and processed Psoraleae Semen. The contents of psoralen and angelicin from Psoraleae Semen showed 0.39% and 0.34% respectively. Processing Psoraleae Semen showed that increased the contents of psoralen (0.52%) and angelicin (0.50%).