The invention discloses a dredging device for a barium sulfate sedimentation tank, which is characterized in that the dredging device is movably mounted in a bearing mounting position on a support bracket via shafting, and the dredging device is controlled to rotate relative to the support bracket under the control of a hydraulic device. The hydraulic device comprises a hydraulic cylinder and a hydraulic rod. The hydraulic cylinder of the hydraulic device is rotatably mounted on the support bracket via a hinge. The hydraulic rod of the hydraulic device is rotatably mounted on the dredging device via a hinge. The problems of low efficiency, low reliability and poor stability of the existing devices are solved. The working height and working angle of the dredging device can be effectively controlled, and thus the reliability of the whole device is improved, and the cost of the whole device is reduced. The dredging device has the advantages that lifting of the hydraulic device is controllable, dredging efficiency is high, working is stable, the service time is long and reliability is high.