The invention relates to a flue gas dust removal device comprising a casing and a filter element. The filter element comprises a rotating part and a blade, a first cavity is arranged in the rotating part, a second cavity is arranged in the blade, the blade is provided with an opening, the rotating part is in communication with the blade, a conical vertical rod connected with the rotating part is arranged in the second cavity, a baffle is slidably arranged on the inner wall of the second cavity, a tension spring is connected between the baffle and the rotating part, the baffle is provided witha through hole, a water pipe is connected with the baffle, the water pipe extends through the opening to the outside of the blade, a pressure valve is arranged on the side wall of the water pipe, andthe water pipe is connected with an internal hollow water ball. The water ball has a water outlet hole, a cleaning block is slidably arranged on the outer wall of the blade, a connecting rod is connected between the cleaning block and the water ball, a pressure block is slidably arranged on the inner wall of the opening, a spring is connected between the inner wall of the blade and the pressure block, a wind wheel is arranged in the casing, the wind wheel drives the rotating part to rotate, the bottom of the casing is provided with a water tank, and the rotating part is communicated with the water tank by a connecting pipe. Th e flue gas dust removal device realizes the automatic cleaning of the filter element.