In this research, the Saccharina japonica macroalgae was pre-treated by diluted acid solution at different concentration to remove inorganic species. The pyrolysis behavior of pre-treated material was performed in a bubbling fluidized-bed reactor. The effects of pyrolysis conditions on product yield and the quality of bio-oil were systematically investigated. When the pyrolysis temperature increased from 450°C to 500°C, the bio-oil yield was between 39.70 wt% and 45.87 wt%. %. The major compounds in the bio-oil were levoglucosan and di-anhydromannitol, showing the highest selectivities of 35.41% and 14.52%, respectively. The selectivity of gas composition (CO, CO2, (C1~C4) hydrocarbon) varied with conditions. The compositions of bio-char were determined by elemental analysis and inductively couple plasma. These results were compared to those obtained from the pyrolysis of raw S. japonica and S. japonica residue after ethanol-extraction.