Abstract: Objective To establish a method for extracting psoralen from the seed of Psoralea corylifolia L. Methods Crushed seed of Psoralea corylifolia L. was soaked with 50% ethyl alcohol solution, and the leaching solution was filtrated and distilled to remove alcohol. A slurry of the sediment was obtained and dissolved in methyl alcohol (MeOH), followed by treatment with active carbon for decoloration and evaporation of MeOH, resulting in a lamellar crystal after the sediment was kept still overnight. MeOH was applied to dilute the sticky solution, and after filteration, a yellow crystal was obtained, recrystallization of which in MeOH yielded white needle-like crystals. Thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) were employed to determine the purity of the resultant substance, and UV and H1-NMR applied to identify its chemical structure. Results and Conclusion The resultant crystal is confirmed to be pure monomers of psoraren with a yield of 0.147% from the seed (m/m) by this simple extraction method.