Abstract: utilize the heavy oil reservoirs by further reducing the viscosity of heavy oil. Based on the analysis of heavy oil properties in Shengli Oilfield, the technology of catalytic viscosity-reduction was developed, and the effect of technology was evaluated under laboratory conditions. By using this technology, the viscosity of heavy oil decreased by 65.0% under the conditions of 1.5% catalyst dosage, reaction temperature of 200 ℃ and reaction time of 20 h.