Abstract:  Pyrolysis experiments of coal, two kinds of municipal sewage sludge (S1 and S2) and the mixture were carried out in nitrogen atmosphere by thermogravimetric analysis. The pyrolysis characteristics of the coal and the municipal sewage sludge samples and the effects of sewage sludge on coal pyrolysis were studied. The coal and sewage sludge have different pyrolysis characteristics parameters in aspects of total weight loss, weight loss rate and volatile release temperature range. Appropriate mixing of S1 and coal is beneficial to the increase in the total weight loss and weight loss rate of pyrolysis reaction. There is partial overlap between the volatile release ranges of S1 and the coal. The inorganic matter in sewage sludge ash has catalytic effect on coal pyrolysis. The pyrolysis of the mixture of coal and S2 shows no obvious synergistic effect. The pyrolysis characteristics of the mixture of coal and municipal sewage sludge are related to the characteristics of samples and the mixing ratio.