A ionic liquid,1-ethyl-3-methylimidazolium acetate in yield of 87%,was synthesized by one-pot method from 1-methylimidozole,bromethyl and lead acetate.The structure was confirmed by UV,IR and elemental analysis.The optimal reaction conditions at 60 ℃ for 20 h were as follows:1-methylimidazole was 100 mmol,n(bromethyl):n(1-methylimidazole):n(lead acetate) was 3.6:2.0:1.0.