Four new isoflavonoids were isolated along with six known related compounds from a rhizome of Belamcandachinensis (Iridaceae), and their structures were characterized as 6''-O-p-hydroxybenzoyliridin, 6''-O-vanilloyliridin, 5,6,7,3'-tetrahydroxy-4'-methoxyisoflavone and 2,3-dihydroirigenin, respectively, on the basis of spectroscopic methods and chemical evidence.