Xinjiang,with abundant low-rank coal and heavy oil resources, holds significant potential for the coal-oil co-liquefaction industry. However, poor fluidity of heavy oil considerably hinders its development. To examine the impact of the compositional structure ofheavy oil on the rheological properties of coal-oil slurry, in this work, five types of heavy oils with distinct properties and two types of industrial circulating solvent oils were selected, and the variation in the rheological properties of the Shangwan coal-oil slurry was investigated. In addition, the compositional structure of the vacuum residue heavy oil was regulated via pre-hydrogenation. Based on the analysis ofthe composition, structure, and rheological properties of heavy oil, the influence of the compositional structure of heavy oil on the rheological properties of coal-oil slurry was revealed. The results indicate that heavy oil in its original state belongs to the Newtonian fluid. However, the addition of coal powder promotes the transform into a pseudoplastic fluid, displaying shear-thinning characteristics. High contentof resin and asphaltene components in heavy oil leads to high viscosity of the formed coal-oil slurry. In addition, the rich thixotropic structure within the system makes the non-Newtonian fluid characteristics more pronounced. The pre-hydrogenation of vacuum residue heavyoil significantly decreases the viscosity of the resultant coal-oil slurry. Notably, the viscosity of the coal-oil slurry by using pre-hydrogenation heavy oil at 380 ℃ for 2 h decreases to 451 mPa·s at 135 ℃ . Pre-hydrogenation facilitates the breakdown of long chains in vacuumresidue oil into short-chain hydrocarbons, the resin and asphaltene components in vacuum residue oil are transformed into saturated andaromatic components, thereby inhibiting the formation of micelles and reducing the viscosity of the coal-oil slurry. In particular, after prehydrogenation at 380 ℃ for 2 h, the resin content was decreased by about 21% compared to the untreated sample, the weight average molecular weight declines to 1 594 Da, and the H content at β position of the aromatic ring increases by about 20%.