The invention provides a slag slurry processing system and method. The slag slurry processing system comprises a settling barrel used for settling sludge, wherein a first pipeline is drawn from the bottom of the settling barrel, and connected to a second pipeline; the second pipeline is connected to an inlet of a slag slurry pump through a first valve; an outlet of the slag slurry pump is connected with a third pipeline; the third pipeline conveys slag slurry pumped by the slag slurry pump to a solid-liquid separation device; the slag slurry pump is connected with a motor; and the power of themotor is variable, so that the flow of the slag slurry pumped from the slag slurry pump can be variable. The slurry treatment system and method provided by the invention can adjust the flow of the slag slurry pumped from the slag slurry pump through setting the power of the motor to be variable according to production needs, so that the solid-liquid separation device can be maximally used and thetreatment efficiency of the slag slurry can be improved.