Abstract: The tests of cocombustion of the blends of coal, coal gangue and sewage sludge were carried out in a thermogravimetric analyzer，model STA 409 PC，in which DSCTGA signals are simultaneously registered and both heat flow and weight loss profiles are obtained. The results indicate that the DTG curves of single coal and coal gangue only have one obvious peak of mass loss, but the DTG curve of sewage sludge has two obvious peaks of mass loss. Also, the DTG curves of the blends have two peaks of mass loss. It is found that the temperature corresponding to the maximum weight loss rate peak lowers with increasing the proportion of coal in the blends. The ignition temperature reduces with increasing the sewage sludge in the blends. When the sewage sludge ratio reaches 70%, the ignition point of the blends of sewage sludge and coal is very close to that of the sewage sludge.