The polymerization of tetrahydrofuran(THF) initiated by heteropolyacid—H3PW12 O40(PW12) in low concentrations could be effectively promoted by epichlorohydrin(ECH).However, the promotion activity of ECH is lower than that of EO or PO, especially when water was introduced. The polymerization started upon addition of epichlorohydrin.When the polymerization has stopped, it could be re-initiated with the addition of a new portion of ECH. The products were found to be copolyether glycols with hydroxyl groups at both ends.The percentage of the hydroxyl group attached to ECH moieties at the polymer chain-ends was higher than 50% of the total hydroxyl end-groups.Most of the ECH moieties in chains attached to hydroxyl end groups,and no primary hydroxyl groups derived from ECH could be detected.