The characteristics of pyrolysis and combustion of low quality mixing coal are investigated by thermogravimetry, in which the coal is mixed by washed coal gangue and washed middling coal. The ignition temperature, burnout temperature, comprehensive combustion parameters and burnout parameters are obtained. The activation energy frequency factor of samples are acquired by analyzing combustion kinetics. It is found that the ignition temperature is 473 ℃ and the burnout temperature is 670 ℃. The activation energy is about 232.55 kJ/mol and the volatile matter is separated out from 415 ℃.