The mixed ionic liquid 2[BMIM]Cl/[BMIM]2SO4 and 2[BPy]Cl/[BPy]2SO4 which were liquid in room temperature were prepared by using low-cost vitriol to partially exchange chlorine ion of [BMIM]Cl and [BPy]Cl. The synthesis of benzyl acetate from sodium acetate and benzyl chloride was investigated in two kinds of mixed ionic liquids, respectively. After comparing the influence of temperature, reaction time and molar ratio of sodium acetate and benzyl chloride on the yield of benzyl acetate, the best condition was obtained. The yield of benzyl acetate would increase by combined 2[BMIM]Cl/[BMIM]2SO4 with 2[BPy]Cl/[BPy]2SO4 and it would reach the maximum when the molar ratio of 2[BMIM]Cl/[BMIM]2SO4 and 2 [BPy]Cl/[BPy]2SO4 is 1∶1. All these results offered a new approach to predigest the production of ionic liquid, decrease the cost and improve applied worthiness.