In order to improve the energy conversion efficiency of hydrogen production from biomass gasification and reduce environmental pollution, it is necessary to study the mechanism of tar catalytic cracking. In present work, in-situ infrared spectroscopy has been used to study the adsorption cracking of toluene on calcined olivine catalyst from room temperature to 500 degrees C. The experimental results indicate that there is no chemical adsorption of toluene on calcined olivine catalyst from room temperature to 200 degrees C. When the temperature is higher than about 300 degrees C, the toluene is chemically adsorbed on alpha-Fe2O3, which is the surface active site of the calcined olivine catalyst. The chemical adsorption occurs between the benzene ring and Fe3+, and it promotes the breakage of methyl from the benzene ring. With the increasing of reaction temperature, the delocalization large it bond in the benzene ring is destroyed by Fe3+, which makes the benzene ring easier to break into smaller products or intermediate products. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.