Abstract: Two different systems for vitrinite and inertinite from Wucaiwan coal were established:no interaction (A) and interaction system (B). Thermogravimetric (TG) and fouriertransform infrared (FT-IR) were used to analyze the pyrolysis products in the two systems. The results show that at 300~450℃ the hydrogen content of B is higher than that of system A, indicating that the reaction of alkyl radical transfer between the vitrinite and inertinite. Meanwhile, the aromatic hydrogen of system B is more than that of system A, which shows that aromatization between vitrinite and inertinite occurs, and a few hydrogen free radicals produced from vitrinite occur macromolecular aromatic structure side chain substitution reaction with inertinite. From 500 to 700℃, the aliphatic and aromatic hydrogen content of system B is lower than that of system A, showing that polycondensation reaction and condensation reaction exist between the vitrinite and inertinite. From 750 to 800℃, aromatic aliphatic hydrogen content of system B is greater than that of system A, which means that vitrinite generates more hydrogen free radicals and occur hydrogenation reaction with inertinite macromolecular aromatic structure as well as side chain substitution reaction with inertinite in system B; From 850 to 900℃, polycyclic aromatic condensation reaction proceeds further between vitrinite and inertinite.