By using the sedimentation column test, the flocculation sedimentation law of the hydraulicdredged slurry is investigated with the case of Dongtou of Wenzhou. The results show that the addition of CPAM can increase the settling rate of slurry, improve the separation rate of slurry, and make the overlying water clear, which can increase the density of sedimentary soil in some extent, and reduce the void ratio of sedimentary soil; At the same time, according to the flocculation sedimentation law of hydraulic-dredged slurry, the flocculation sedimentation model of CPAM as flocculant to treat the dredger filled slurry is put forward, which is divided into four stages of flocculation sedimentation, rapid settling, slow settling and stabilization.