Cutter suction dredger is currently an extensively applied ship in beach dredging projects. Cutter suction dredger uses rotary reamers to loosen soil in the bottom of the river or sea, blends the soil with water and mud into slurry, then has the slurry sucked by a slurry sucking pipe to the pump and delivers the slurry to the slurry discharge area thousand meters away and achieves the dual purposes of dredging channels and land reclamation. During construction of such dredgers, it integrates dredging, mud conveying and mud unloading into a whole by itself and achieves rather high production efficiency.