A common way to research thermal conversion processes is through the analysis of chemical kinetics. In this article, a semi-quantitative method was established to calculate the chemical kinetics of biomass pyrolysis through differential and integral routes by using the thermal analysis-mass spectrometry (TA-MS) signals of pyrolytic products. The method can be applicable when there is a difficulty in quantitative analysis. Kinetic parameters calculated by the method were compared with those determined by thermogravimetric data. The accuracy and precision of the method may be improved by increasing the frequency of data recording or product sampling. The method should be widely applicable as long as the instrumental signals of products are sufficient and satisfactory. Therefore, various reactions can be comprehensively discussed and understood. (C) 2013 Elsevier Ltd. All rights reserved.