Starting from resorcinol and p-methoxylphenylacetic, a facile one-pot synthesis of 7-Hydroxy-4’-methoxyl-isoflavone (Ⅰ) was achieved in 84.0％ yield under ultrasonic irradiation for the first time in the presence of boron trifluoride-diethyl ether, DMF and methanesulfonyl chloride. Then (Ⅰ) reacted with benzoyl chloride, acetyl chloride, 2-phenoxyacetyl chloride, cinnamoyl chloride and 2-hydroxybenzoyl chloride to give five isoflavone derivatives (Ⅱa~e) respectively in 57.1％, 60.6%, 59.4%, 61.1% and 50.4%. Their structures were confirmed by IR, H1 NMR, C13 NMR and MS spectroscopy. Finally the pharmacological assays of anti-osteoporosis indicated that these compounds could promote the proliferation of rat’s osteoblast in vitvo to a certain degree.