The composition of biomass pyrolysis vapors is complex. Their separation properties were investigated by using fractional condensation under different temperature. According to the distinct dew points of the compound containing

the enrichments with different bio-oil grouping were produced by controlling condensed temperature such as 300℃

100℃

0℃ and -20℃

and so four groups of bio-oil samples were obtained during our experiment of fractional condensation and their characteristics of each fraction were studied and analyzed. The yield of liquid condensed in 0℃ is the highest and more than 50% of the whole bio-oil

while that did in 100℃ contained the organics with molecular weight of 80 to 200

mainly fusel phenol compounds. The fraction collected in 300℃ was bitumen

which did not contain moisture

look like solid carbon and there was no liquidity and viscosity. Water and organic acids had well be separated from bio-oil in fractional condensation

more than 80% water and nearly all the organic acids were collected in the enrichments at 0℃ and -20℃. The distribution of some typical components including acetic acid

phenols

guaiacol

and PAH under different condensed temperature was analyzed by GC-MS

and enrichment rule was obtained based on behaviors of typical compounds condensing in bio-oil.