Abstract: In order to study the gas products and kinetic parameters of coal pyrolysis, the pyrolysis experiment was carried out for four coal samples with different thermal evolution using Thermo Gravimetric-Infrared-Mass spectrometry (TG-IR-MS). The variation trend of components and amount of released gases of four kinds of coal samples during pyrolysis at temperature range of 30 to 1℃ 100 with the heating rate of 10/min under helium℃℃ atmosphere was recorded in real time. The thermal analysis results showed that the weight loss rate and the maximum weight loss rate of coal decreased gradually with the increase of the thermal evolution degree, and was positively related to the voltile of dry ash-free basis. Some small-molecule gases like H₂O, CH₄, CO₂, H₂ and SO₂ were released gradually with pyrolysis temperature. With the increase of the coalification degree, the peaks of released gases gradually shifted to higher temperature. Pyrolysis kinetic analysis of coals with different coalification degree showed that the activation energy decreased with the metamorphism degree, illustrating that the heat effect strength and the ability of pyrolysis reactions decreased gradually.