The pyrolysis behaviors of several agricultural residues have been investigated by using thermogravimetric analysis. The evolving rates of the gaseous products during the pyrolysis such as H-2, CH4, H2O, CO2 and CO2 were also measured by the TG-MS techniques. Without any assumption and mathematical fitting, we could obtain the very proper kinetic parameters (the distribution curve of activation energy, f(E), and the activation energy dependent frequency factor, k(0)(E)) of biomass pyrolysis by utilizing the distributed activation energy model (DAEM) proposed by Miura and Maki [Miura K, Maki T. Energ Fuel 1998; 12:864]. The peaks of f(E) curve for rice straw, rice husk, corncob and cellulose were found to be 170,174,183, and 185 kJ/mol, respectively. The k(0) value increased from an order of 10(11) to an order of 10(18) s(-1), while E increased from 120 to 250 kJ/mol. The catalytic effects of alkali and alkaline earth metals during the pyrolysis play a major role in the variation of f(E) curve among the different biomass species. (C) 2007 Elsevier Ltd. All rights reserved.