Shengli lignite was sequentially extracted with aqueous NaOH solution, n-hexane, dichloromethane (DCM), isometric benzene and ethanol (IMBE), and acetone to obtain extracts 1-5 (E-1-E-5). Each extract was biotreated by an isolated fungus WF8 under the same conditions. The results show that E-1 is much more susceptible to the bioliquefaction (BL) than other extracts. The BL of E-1 proceeded via the cleavage of C-O-C and Si-O bonds to some extent, while most of the methylaromatic and -COOH-containing moieties in E-1 are inert toward BL by WF8. E-1 has largely similar molecular mass distribution (MMD) to unliquefied E-1, but quite different MMD from bioliquefied E-1, further indicating that the BL of E-1 proceeded via biochemical reactions by WF8.