In this work, to better understand the thermal behavior of sodium species in the utilization of Zhundong coal (ZDC) from Xinjiang, northwestern China, the transformations of sodium species in direct liquefaction of ZDC were investigated in a bench-scale autoclave. The effects of sodium species with different occurrence modes on the product distributions in ZDC liquefaction were also examined. The results show that the transformations of sodium species strongly depend on the occurrence modes and the liquefaction temperatures. Below 370 degrees C, ammonium acetate-soluble sodium species (AS-Na) could be partly transformed into water-soluble ones (WS-Na). However, when the temperatures further increased, the reactions between AS-Na and silicates to form hydrochloric acid-insoluble sodium species (HIS-Na) predominated and the residue formed in this process was firmly adhered to the bottom of the autoclave. The retention ratios of sodium species over all temperature ranges are significantly higher (>89 wt %) than those in ZDC pyrolysis, which implies a significant enrichment of sodium species in liquefaction residues. Besides, both WS-Na and AS-Na are verified to be the detrimental species in ZDC liquefaction; especially, the oil generation could be more severely inhibited by AS-Na, and this negative effect could be mitigated by demineralization with hydrochloric acid.