Three kinds of ionic liquids of 1-butyl-3-methylimidazolium zinc chloride were synthesized by 1-butyl-3-methylimidazolium chloride and zinc chloride using microwave-assisted ion-exchange method. The influence of solvents on the synthesis of ionic liquid was also investigated. The glycolysis of poly(ethylene terephthalate) was also studied using the synthesized ionic liquids as catalysts and glycol as solvent by microwave-assisted method. The influence of the dosage of ionic liquid, reacting temperature, reacting time and dosage of solvent on the glycolysis of PET was studied according to the yield of recovered terephthalic acid. The results show that the corresponding ionic liquids could all be synthesized in 30 mins by microwave-assisted ion-exchange method. The yields of the three kind of ionic liquids are all more than 90% using dioxane as solvent. [Bmim][Zn2Cl5] exhibits higher catalytic activity for the glycolysis of PET by microwave-assisted method. The recovery yield of terephthalic acid is more than 20% by using [Bmim][Zn2Cl5] as the catalyst.