Fast pyrolysis experiments of larch sawdust were conducted in a conical spouted-bed reactor to study the influences of reaction temperature, inlet gas velocity, feeding rate, and particle size on the product yield and pyrolysis oil quality. For the first time, the optimal conditions were determined for various pyrolysis operations of such reactor to increase the yield and quality of pyrolysis oil. The results demonstrate that the biomass particle size, reaction temperature, biomass feeding rate, and inlet gas velocity all affected the quality and yield of the pyrolysis oil, in this order.