Abstract: The mechanism of adding sodium carboxymethyl cellulose (CMC) to improve the strength of hematite ore and coal briquettes was investigated by infrared spectroscopy (IRS), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. It is found that -OH and -COOH in CMC chemically absorb at the surface of hematite ore and reduce the hydrophilic character of ore particles, while hydrocarbon chains in CMC bond on the surface of coal and reduce the hydrophobic character of coal particles. Hematite ore and coal grains are bonded by the organic skeleton of CMC, and form a supporting network bridged by CMC chains between the particles to ensure the good strength of the briquettes. Therefore, the strength of hematite ore and coal briquettes is highly improved with the addition of CMC.