Sludge dredging equipment for water conservancy construction and dredging method thereof

The sludge dredging equipment comprises a ship body, a hollow cylinder is inserted in the middle of the bottom face of the ship body, a spiral shaft is arranged in the hollow cylinder, and a plurality of spiral blades are arranged on the spiral shaft; a transverse plate is arranged at the top of the hollow cylinder, a hollow shaft is inserted in the middle of the top surface of the transverse plate, a polygonal shaft is inserted in the middle of the hollow shaft, a rotating disc is arranged at the top of the polygonal shaft, and the bottom end part of the polygonal shaft is coaxially connected with the top end part of the spiral shaft; the outer end of each limiting plate is provided with a scraping plate, the sleeve is connected with a transverse plate through a linkage mechanism, and the transverse plate is connected with the rotating disc through a reciprocating mechanism. The problem that the river bottom sludge cleaning effect is poor is solved, the river bottom sludge is conveniently scattered and clean