Abstract: Pyrolysis and combustibility of coal and coal black liquor slurry were studied on the thermobalance. The characteristics of pyrolysis, combustion and carbon conversion are all obtained under different heating rates . It is shown that the combustion of coal black liquor slurry is catalyzed by sodium and its compound ,and also the organic matter composition plays a certain role in the burning of coal black liquor slurry. The activation energy of coal and coal black liquor slurry combustion at the heating rate of 20 ℃/min are 12.98 kJ/mol and 106.59 kJ/mol, respectively ，which indicates that the combustion characteristic of coal black liquor slurry is better than that of coal.