A novel CIL of N-butyl-N-methyl imidazolium-D-(-)-tartrate has been designed and synthesized by neutralization reaction. Its structure was characterized by 1H-NMR and 13C-NMR spectra, the optical rotation was characterized by polarimeter with the value of-15.0º, and the purity was characterized by ion chromatography with the value of 98.4%.