A new quaternary ammonium heteropolyoxotungstant (cat. C) is prepared and characterized. And the cat. C also is an reaction-controlled phase-transfer catalyst. The catalytic system of O2/EAHQ (2-ethylanthrahydroquinone)/cat.c is used for the epoxidation of propylene.Under the optimal conditions, the yield of propylene oxide based on EAHQ is 84.1%, the selectivity for propylene oxide based on propylene is 99.8% and the conversion ofpropylene based on EAHQ is 84.3%. The cat.c precipitates after the epoxidation reaction for easy separation.The cat. C is stable enough to be recycled three times without any loss in selectivity.