Abstract: Combining with the characteristics of sludge and the advantages of superheated steam drying used in high humidity or thermal insensitive material，a superheated steam drying experimental device was designed and fabricated． Main components and working principles of the experimental device were described in this paper． In order to study the drying characteristic of sludge in superheated steam drying，drying experiments were carried out at different superheated steam temperature of 160 ℃， 220 ℃ and 280 ℃，and different sludge sample thickness of 4，6 and 10 mm，respectively． The results showed that the increasing of sludge moisture content in the beginning of the drying process caused a longer drying time． When the superheated steam temperature was higher and the thickness of sludge was thinner，the sludge drying rate was faster and shorter time was needed to dry the sludge to the equivalent moisture．