Abstract: The phosphorus content of sewage sludge ash is higher than that of Shenfu coal, and its main phosphoric crystalline minerals are calcium iron phosphate and a certain amount of aluminum phosphate. The volatilization of phosphorus during co-pyrolysis of sewage sludge and Shenfu coal was studied with a high frequency furnace reactor in laboratory scale. It has been found that after pyrolysis most of the phosphorus in fuels is deposited in char. The volatilization ratio of phosphorus increases at first and then decreases with the increase of sewage sludge ratio in fuels. And it monotonically increases with the pyrolysis temperature. Organophosphorus compounds make up the main part of volatized phosphorus when pyrolysis temperature is less than 1 100 ℃ and its volatilization ratio is lower than 3.2%. Inorganic phosphorus does not volatilize obviously until 1 200 ℃, and the highest volatilization ratio of phosphorus is 33.0% at 1 300 ℃.