A new xanthone, 1,7-dihydroxy-2,3,5,6-tetramethoxyxanthone (1), together with eight known compounds including one xanthone (2) and seven isoflavones (3 9) has been isolated from the leaves of Millettia pachyloba. This is the first report on the isolation of xanthone from the genus Millettia. The structure of the compound 1 was elucidated on the basis of spectroscopic data interpretation, including 1D and 2D NMR and HREIMS. Compound 1 exhibited weak cytotoxicity against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7 and SW480.