The invention discloses an aquarium cleaning brush. The brush comprises an inner brush body and an outer brush body. The inner brush body comprises a sand discharging stable fin, a bottom plate groove, a cover body, a miniature nylon loop surface and a magnet, and the outer brush body comprises a bottom plate groove, a cover body, magnets and a plastic fiber rough surface (a sponge or a scouring pad). The brush is used for cleaning away algae and dirt on the plane or curved wall of an aquarium, and time and strength are saved; the brush is unlikely to fall off and has the self-cleaning capability of automatically discharging the wiped off algae or dirt for filtering circulation, and the sand at the bottom of the aquarium can be discharged to prevent the situation that the sand gets stuck between the brush surface and the wall of the aquarium and scratches the wall of the aquarium.