Firstly the impacts of heating temperature and rate of microwave on dewater ability and morphological feature of sewage sludge were investigated. Then CST, viscosity, SV, moisture content, COD, Zeta electric potential and morphological feature were tested. It is shown that the lowest CST of reclaimed water plant is 4.2s while the heating rate is 10℃/min and heating temperature is 80℃. SV, viscosity, moisture content of waste water plant sludge decrease and COD increases when heating temperature is higher. It is indicated that morphology of sludge changes under different heating conditions from fractal dimension and particle size data which is analyzed from image and calculated from cumulative weight percentage undersize of sludge particle. After 60~80℃ microwave pretreatment, dewater ability is proved.