Abstract: In order to improve the existing technologies for the pyrolysis of biomass on fluidized bed reactor and to determine optimal experimental conditions for maximizing the yield of bio-oil, a plasma internally heated fluidized bed reactor (52 mm in diameter and 1150 mm in height) was developed and a series of biomass pyrolysis experiments were conducted on the reactor. Corn stalk powder was used for the pyrolysis experiments on the fluidized bed reactor at different reaction temperatures and feeding rates. The influences of reaction temperature and feeding rate on the yield of bio-oil were then discussed. The experimental results show that the yield of bio-oil reaches the maximum at 750K with the feeding rate ranging of 0.6～0.7 kg/h. The chemical compositions of the bio-oil were analyzed by gas chromatography-mass spectrometry (GC-MC). The major chemical compositions detected were acetic acid, 2-propanone, 1-hydroxy, water, acetaldehyde, hydroxy, furfural, etc. Because of high content of oxygen and water, polymerization may react easily and the heat value is low. The characterization method could be adopted in further studies for bio-oils from other materials and upgrading test of bio-oil.