The invention discloses a coal preparation plant reuse water desliming and deslagging device. The device comprises an outer cylindrical shell, an inner cylindrical shell and a rotary drum which are horizontally arranged, and further comprises a motor, a rotating shaft, a feeding tube, a driving gear, a driven gear, a ring gear, a spiral blade, a filter screen cover, a deslagging port, a deslaggingtube and a water outlet. The motor can drive the rotary drum to rapidly rotate, the transmission relationship among the driving gear, the driven gear and the ring gear which are mutually engaged makes solid particles rapidly settle on the inner wall of the filter screen cover, water free from impurities permeates through the filter screen cover, enters a space between the outer cylindrical shelland the filter screen cover, and is discharged through the water outlet, and impurities are transmitted to the left end of the spiral blade from the right end, are discharged into the deslagging tube,and are discharged out of the outer cylindrical shell in order to complete the desliming and deslagging of coal preparation plant reuse water. The device has the advantages of simple structure, low cost, convenience in use, good desliming and deslagging effects on the coal preparation plant reuse water, and convenience in promotion and use.