A new type of rapid and automatic proximate analyzer for coal based on isothermal thermogravimetric analysis (TGA) with twin-furnace is introduced in this paper. This automatic proximate analyzer was developed by combination with some novel technologies, such as the automatic weighting method for multi-samples in a high temperature and dynamic gas flow circumstance, the self-protection system for the electric balance, and the optimal method and procedure for coal analysis process. Additionally, the comparison between standard values and the measurement values derived from the new instrument of standard coals was presented. (C) 2003 Elsevier B.V. All rights reserved.