Microwave pyrolysis of Douglas fir sawdust pellet was investigated to determine the effects of reaction temperature and time on the yields of bio-oil, biogas, and biochar using a central composition design (CCD) and response surface analysis. The research results indicated that thermochemical conversion reactions can take place rapidly in large-sized biomass pellet by using microwave pyrolysis. The yields of bio-oil and biogas were increased with the reaction temperature and time. The highest yield of bio-oil was 53.9% (wet biomass basis) obtained at 470.7°C and 15min. GC/MS analysis indicated that the bio-oils were mainly composed of phenols, guaiacols, furans, ketones/aldehydes, and organic acids. The phenols and guaiacols accounted for the largest amount of chemicals in the bio-oil, which represented 59.7-78.6% under different conditions. The biogases contained high value chemicals, such as carbon monoxide, methane, and short chain hydrocarbons. A third-order reaction mechanism fits well the microwave pyrolysis of Douglas fir pellet with activation energy of 33.5 kJ/mol and a frequency factor of 3.03 s-1.