Moll method used in extracting the kinetic parameters of thermal decomposition of biomass materials is theoretically analyzed and the limitation of the method is critically examined. It is demonstrated that Moll method can only be used under strict conditions within narrow temperature intervals. In light of the idea of Moll method and also in view of the limitations of Moll method, a two-point data set method is developed for the kinetic analysis of the decomposition of biomass materials in air, using single heating rate mass-loss curve. The method is justified by comparing the resulted kinetic parameters with those by integral and differential methods. Compared with Moll method, the new method is applicable to the mass-loss data within wide temperature intervals, whereby the kinetic parameters (especially the activation energy) can be evaluated without any prior knowledge of reaction order, with fairly high reliability. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 524-530, 2009