The pyridine quaternary salt was synthesized by the reaction of pyridine with 1-butyl chloride under dark condition.Then it was used as an ionic liquid catalyst to prepare propylene carbonate (PC)from carbon dioxide and propylene.The effects of reaction pressure,reaction temperature,reaction time and catalyst dosage on the yield of PC were investigated.Under optimum reaction conditions (5.0 MPa,150℃,5 h),the yield of PC could reach 88.1%.