Abstract: A systematic research on the combustion characteristics of Guizhou lignite, Sanjiang coal and Sanjiang char had been done using STA 409C Netzh- thermogravimetric analyzer. The effects of particle diameter and heating rate on maximum mass loss rate, ignition point and combustibility were analyzed. The decrease of particle diameter can reduce the ignition point and improve the combustibility. When particle size is 100～120 mesh and heating rate is 25 ℃/min, the combustibility of samples is the best. The combustion reactions are one-order reaction and kinetics parameters (activation energy E and frequency factor A) were obtained by the method of Coats-Redfern basing on experimental data. Activation energy of Guizhou lignite, Sanjiang coal and Sanjiang char are 100.0～163.6 kJ/mol, 73.4～161.2 kJ/mol, 68.3～178.1 kJ/mol.