Abstract: The liquefaction behaviors of Xianfeng lignite (XL) in ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate (BmimBF₄) under mild condition-350 ℃ were studied. The effect of catalysts (FeS, ZnCl₂, AlCl₃ and FeCl₃) on the XL liquefaction in BmimBF₄ were investigated and the liquefaction products obtained were analyzed by FT-IR spectra. It is found that the XL has a good hyrogenation activity in the presence of BmimBF₄, catalysts and tetralin (THN). XL liquefied product yield reaches to about 66.2% and the main liquefaction product is heavy fraction-tetrahydrofuran soluble (THFS) and tetrahydrofuran insoluble/N-methyl-2-pyrrolididinone soluble fractions (NS). The analyses of liquefied product by FT-IR show that the type of catalyst significantly affects the distrubution and structure of liquefied product.