Fluidized bed pyrolysis has been recognized as an innovative technology for sewage sludge treatment. The physical and attrition properties of sewage sludge are changed through the fluidized bed pyrolysis. The minimum fluidization velocities and attrition rate constants for sewage sludge and sludge based-char were obtained from pressure drop and attrition tests. As a result, sewage sludge with 20% moisture content and char were classified as Geldart B solids and the superficial gas velocity for bubbling fluidization was 0.2142-0.8755m/s. In addition, attrition of the sewage sludge and char was more affected by particle size than by material type. The equations for the overall attrition rate constants are Ka×105=1.09U.14.82 for sludge and ln ka=0.1(U.Umf).13.63 for char, respectively.