Fast pyrolysis experiments of pine and corncob were conducted in the fluidized bed reactor with a feed rate of 1kg/h, and bio-oils with different properties were obtained by spray condensation. Effect of condensing temperature on properties of bio-oils was investigated. The results of experiments showed that yields of bio-oils from pine and corncob were reduced by 23.1% and 20.8% respectively, and water contents were also decreased by 11% and 18% respectively, while viscosities went up by 181cSt and 10cSt respectively, and heat values also increased by 6.23MJ/kg and 5.04MJ/kg respectively when condensing temperature rose from 25℃ to 75℃. The chemical compositions and structures of bio oil were analyzed by gas chromatography/mass spectrometry (GC/MS) and nuclear magnetic resonance spectroscopy (NMR). From the GC/MS spectra it was observed that the contents of anhydrosugar significantly increased in bio-oil from pine, while the contents of most light components decreased with the rise of condensing temperature. In bio-oil from corncob contents of anhydrosugars and phenols were both slightly enhanced, while contents of organic acids, aldehydes and ketones were reduced in bio-oil from corncob. The 13C spectra revealed that the content of alkyl carbon decreased, while the content of aromatic carbon increased in bio-oils with the rise of condensing temperature, and thus aromaticity of bio-oil was raised.