Abstract: In order to investigate the pyrolysis characteristics and the distribution of gas phase product of lignite, pyrolysis experiments at different heating rates were carried out with a thermogravimetric mass spectrometry (TG-MS), and the weight loss of coal samples at different heating rates, the change of release process of CO and H2, and the calorific value of the pyrolysis gas and the cold gas efficiency were explored and calculated. Research results show that the release rate of water vapor at different heating rates is equal, which is not related to the pyrolysis heating rate. The mass of coal sample decreases gradually with the increase of pyrolysis time. At different heating rates, the final residual mass of pyrolysis coal samples is not the same, and the average remaining mass is 6.51mg. When the pyrolysis conversion is small, the activation energy E value is larger, and the pre exponential factor A is higher. With the increasing of the pyrolysis conversion rate, the activation energy decreased, which indicates that with the increase of pyrolysis temperature, coal molecular absorption energy to overcome the reaction barrier difference decreases, the pyrolysis rate increases. The release of CO and H2 can be divided into three stages, and the release peak temperature moves to the high temperature with the increase of heating rate. The calorific value of gas product and cold gas efficiency exhibit a wavelike trend.