Abstract: To address the high nitrogen and oxygen content in bio-oil and catalyst deactivation during catalytic pyrolysis of algal biomass, this study investigated the pyrolysis characteristics of spirulina catalyzed by a molten salt-coupled zeolite/cerium-based catalyst system. The denitrification and deoxygenation effects of the coupled system on Spirulina pyrolysis bio-oil were examined, and the mechanism by which molten carbonate inhibits catalyst deactivation was thoroughly investigated. The results demonstrate that molten carbonate effectively reduces the yield of nitrogen and oxygen elements in bio-oil by 25.90% and 28.53%, respectively. Compared with catalytic pyrolysis alone, the molten carbonate coupled with H-β（Si/Al=26） and NiCe/Al₂O₃ reduced the content of oxygen/nitrogen-containing compounds in bio-oil by 71.49%/31.20% and 53.14%/39.50%, respectively, while increasing aromatic compound content during single pyrolysis by only 4.02% and 11.02%. After coupling with molten carbonate, the coke deposition mass on H-β（Si/Al=26） decreased by 31.60%, and that on NiCe/Al₂O₃ decreased by 20.97% after single pyrolysis. Molten carbonate inhibits coke formation by removing oxygen-containing compounds and nitrogen-containing heterocycles from volatiles, while its reaction with basic amides/amines prevents deactivation of active sites. Additionally, molten salt suppresses condensation reactions related to carbon double bonds and amino groups, enhances the saturation of heavy components, and inhibits their further polymerization into coke. Owing to the improved catalyst stability from molten carbonate, the aromatic compound content in bio-oil obtained after 5 cycles using the coupled system increased by over 48% compared to conventional catalytic pyrolysis.