The combustion characteristics of the mixtures, which are made from different proportions of paper mill sludge and coal, were studied by the thermogravimetric analysis (TG-DTG) at different heating rates. The results showed that there were obviously three temperature zones in the paper mill sludge combustion curves, which is respectively corresponding to two devolatilization stages and a fixed carbon combustion stage. In these stages, the weight of sludge was lost promptly. When the proportions of sludge – coal blends were rather different, ignition point obviously shifted to the larger proportions, and DTG curve was more closed to the larger proportions. During the combustion process of the mixture, the paper mill sludge and the coal had basically maintained their own devolatilisation characteristics. And the comprehensive combustion characteristic index S of sludge-coal blend declined, demonstrating that higher volatility had better combustion characteristics. As the heating rate and the proportions of coal increasing, total weight loss rate increased, while burnout index Cb raised.