Abstract: Six different solvents were used as swelling agents to pretreat bituminous coal. The coal before and after treatments was characterized by SEM, FTIR and solubility measurements, and liquefaction experiments were also performed on raw coal (C_R) and six swollen coals. The results show that swelling can expand coal structure, although FTIR results indicate that coal microstructure is not broken. The solubility difference between N, N-dimethylformamide (DMF) and C_R is the smallest for the six solvents used, and DMF has the best swelling effect with swelling degree of 1.71. In addition, the solubility of C_DMF is the lowest among the six swollen coals with the best direct liquefaction performance. Compared with C_R, the solubility of C_DMF decreases by 2.73%, gas yield decreases by 89.71%, and the liquid yield and conversion rate increase by 27.48% and 5.35%, respectively.