The microwave and centrifuge technologies were combined to release bound water and improve dewatering capability, which was carried out by measuring the Capillary Suction Time (CST), rheological parameters and water content, collecting sludge images to extract morphological features and analyze fractal dimension. The experimental results indicated that water content decreased with an appropriate increase of centrifugal speed and temperature. When microwave power was 1000 W, microwave temperature was 50℃, centrifugal speed was 2000 r/min and centrifugal time was 15 min, the water content of sludge reached the lowest value of 83.75%. The fractal dimension of sludge was in the range of 2.4-2.8 after the pretreatment of microwave. A model of dewatering characteristics was established by fitting dewatering capability parameters and water content, which would contribute to predicting and improving dewatering capability of sludge.