Recycling-sludge operation is applied in the Feng-Yuan Water Treatment Facility to treat low turbidity source water. By employing fractal dimension analysis and the dilatometry technique, the effects of recycling-sludge operation on the structure and moisture content of sludge flocs are studied. As the results show, the recycling-sludge operation can decrease the average bound water content by nearly 13-24% and increase the effective flee density, thereby forming a compact structure with a high fractal dimension and low flee porosity. The results also indicate that a significant correlation arises between the fractal dimensions and the bound water content of the sludge flocs.