Abstract: Bridging flocculation settlement experiment for high-concentration turbid liquor (HCTL) represented by Yellow River sediments indicates that the structures of aggregates have a fractal property. Fractal structures of aggregates can change from a big size and loose and open-branching DLCA structure to a small size and minimum average void and compact optimum RLCA structure gradually, and then the fractal structures become loose and vulnerable again. The optimum fractal structure of aggregates will only have a certain lifetime. Development and evolution irregularity of fractal structures of aggregates can be characterized by the parameter `fractal dimension D’. The `fractal dimension D’ can be used as a tool to obtain ideal structures of aggregates quantitatively, which has a better settling and dewatering behaviors. Fractal structures of aggregates are affected by raw turbidity of the liquor, stirring rates and stirring time, etc.