Abstract: Based on the analyses of physical and chemical features of oily sludge, the influencing factors on the drying characteristics of sewage sludge in Liaohe Oil Field were studied and some conclusions were drawn as follows. The mixture ratio of coal, sludge particle size and drying air temperature and flowrate are the main influencing factors on the drying characteristics of the oily sludge, among which the last two affect to a certain extent. The greater the mixture ratio of coal, the smaller the sludge particle size; and the higher the temperature the drying air, the higher the flowrate of drying air and the drying rate. Moreover, the sludge drying effect will be obviously better if the mixture ratio of coal is about 20%, the sludge particle size approximately 20 mm and the suitable temperature of drying air near 125°C.