The invention discloses a solid-liquid mixing device. The mixing device comprises a stock bin, a working cavity, a dispersing disk, a first motor, a centrifugal pump, a stirring tank, stirring vanes and a second motor, wherein the dispersing disk is arranged inside the working cavity; a first pipeline communicated to the feed opening of the working cavity is arranged at the discharge opening of the stock bin; a second pipeline communicated to the feed opening of the centrifugal pump is arranged at the discharge opening of the working cavity; a third pipeline communicated with the discharge opening of the stirring tank is arranged at the feed opening of the centrifugal pump; a forth pipeline communicated to the feed opening of the stirring tank is arranged at the discharge opening of the centrifugal pump; the stirring vanes are arranged inside the stirring tank. The mixing device adopts vacuum generated by the centrifugal pump in the high rotating speed to inhale powder in the stock bin into the working cavity for smashing; the smashed powder enters the centrifugal pump to be mixed with a premixed sizing agent returning from the stirring tank, and reenter the stirring tank; the mixing device adopts vacuum to enable powdery or granular solids to have a relatively high impact speed to enter the premixed sizing agent so as to increase the dispersing efficiency of the solids, and has the advantages of being simple in structure, easy to operate, high in dispersing efficiency and the like.