Co-pyrolysis of wood biomass and waste tire with such catalysts as SBA-15, MCM-41 and HZSM-5 was carried out in a fixed-bed reactor. The influences of the mixture composition on liquid yield and characteristics of the oil were investigated. The properties of the oil were determined by gel permeation chromatograph (GPC), elemental analyzer (EA), thermal analyzer (TA), densimeter, ubbelohde viscosimeter and compared with that of diesel oil 0#. The contents of the polycyclic aromatic hydrocarbons (PAHs) in the oils were also determined by gas chromatograph (GC). The result shows that co-pyrolysis is in favor of inhibiting the formation of polycyclic aromatic hydrocarbons (PAHs) produced from tire. There exist a hydrogen transfer and a synthetic effect during co-pyrolysis of the biomass and tire. They improve the quality of the oil. SBA-15 as a catalyst is more significant than MCM-41 or HZSM-5 for reducing the density and viscosity of the oil and it can effectively decompose some large molecular compounds into small ones. (c) 2008 Elsevier B.V. All rights reserved.