The invention provides a slurry circulating device and a dispatching method. The slurry circulating device comprises a permanent magnet synchronous frequency conversion motor, a coupling and a slurrycirculating pump; and the dispatching method comprises the following steps: calculation of the lift reduction amount of the slurry circulating pump, the flow rate of the slurry circulating pump and amotor frequency adjustment value; and adjustment of a motor frequency. Through the slurry circulating device and the dispatching method provided by the invention, the problem of deviation of the design from actual operation of the slurry circulating pump due to fluctuation of the operation load of a power station unit and large deviation of the sulfur content from the designed value of coal is solved; the effects of no foundation modification, less investment and accurately-controlled operation for the slurry circulating pump are achieved; energy conservation and consumption reduction of unitoperation can be realized; and the cost of on-site operation is reduced.