Abstract: Effect of temperature of biomass fast pyrolysis on yield and properties including water content, density, viscosity and composition of chemical compound of bio-oil was studied in a self manufactured small fluidized bed reactor with sawdust. Results showed that when pyrolysis temperatures were 475℃, 500℃ and 550℃, the highest average bio-oil yield was 58.74wt% at 500℃; water contents of bio-oil were 42.5%, 46.0% and 40.7%, respectively; the densities of bio-oil were 1140 kg/m³, 1148 kg/m³ and 1151 kg/m³, respectively; kinematics viscosities of bio-oil were 4.51 cSt, 3.87 cSt and 4.73 cSt, respectively. When temperature of pyrolysis was increased, the density of bio-oil was slightly increased, and its water content and kinematics viscosity had no regular changes. In addition, the kinematics viscosity was decreased with the increase of water content. The temperature of pyrolysis had a certain influence on the content of common chemical compound of bio-oil, but not apparent. The bio-oil was composed of a very complex mixture of oxygenated unsaturated hydrocarbon ramifications and their carbon numbers were ranged within 2～10. Moreover, it showed that the increase of pyrolysis temperature was in favour of the production of furfural and phenol compound, but not in favour of the production of acetic acid. The research provided a scientific reference for the production and application of bio-oil.