Abstract: On the basis of high content of water in brown coal, the hydro-liquefaction behavior of Shengli(SL) coal under different atmospheres using water as solvent was preliminarily studied, comparing with the liquefaction using tetralin (THN) as solvent. In 380 ℃, H2/THN system, the conversion of SL coal gets to 85.3% with 73.2% oil+gas yield and 12.1% asphaltene yield. The active H stabbing residuals which come from the pyrolysis of the coal mainly comes from the hydrogen donor solvent, not directly from H2. In the liquefaction tests with water as solvent, the conversion was higher in CO atmosphere than that in H2 or N2 atmospheres, getting to 70.2% with 58.1% oil+gas yield and 12.1% asphaltene yield. In CO/H2O system, the water gas shift reaction (WGSR) produces high active H which can stab the residuals in order to improve the liquefaction conversion. The results indicate that the liquefaction process in CO/H2O is feasible for brown coal with high content of water.