A new aurone, (2 Z)-2-[(4′-hydroxyphenyl) methylene]-6-methoxy-7-prenyl-3(2 H)-benzofurane (1), together with 6 known compounds (2-7), was isolated from the EtOAc-soluble extract of the seeds of Psoralea corylifolia. Their structures were elucidated on the basis of spectroscopic methods. All compounds were evaluated for in vitro inhibitory activity against a human colon cancer cell line (SW620). Compounds 1 to 3 showed moderate cytotoxicity against the SW620 cells with IC50 values ranging from 24.31 to 28.72 μM. Among these compounds, 1 showed higher cytotoxicity against SW620 cells with an IC50 value of 24.31 μM.