The invention discloses a system for reducing the moisture content of water slag. The system for reducing the moisture content of the water slag comprises a water slag collector, a centrifugal separating device, a conveyor belt and a dry slag collecting device, wherein the water slag collector comprises a condensing device, a filtrate outlet and a wet slag outlet; the condensing device is arrangedat the upper end of the water slag collector, the filtrate outlet communicates with a filtrate pool and is provided with a filter screen, and the wet slag outlet is located above the filter screen inthe water slag collector and is provided with a scraping plate; the centrifugal separating device is connected with the wet slag outlet; the conveyor belt is connected with a slag discharging port ofthe centrifugal separating device and is used for conveying dry slag discharged from the slag discharging port of the centrifugal separating device to the dry slag collecting device; and the conveyorbelt is provided with a waste heat evaporation piping system, and an exhaust gas blowing system is arranged in the dry slag collecting device. The system for reducing the moisture content of the water slag has the advantages of good drying effect, small pollution and low energy loss, the water slag obtained through the system is low in moisture content, and the conveying cost can be effectively reduced.