Abstract: A kinetic Arrhenius first-order rate model was used to investigate biomass flash pyrolysis volatilization characteristics in this paper. Through theoretical analysis, the values of activation energy and frequency factors were obtained. Based on experiments of various biomass flash pyrolysis volatilization performed with a laminar entrained flow reactor, the model was checked by experimental data acquired with ash tracer method. The researches suggest that the experimental data fit the model well. It may apply to different kinds of biomass, while the activation energy and frequency factors are different relating to different kinds of biomass. The model may be used to describe the characteristics of biomass flash pyrolysis.