A complex high-density soybean grinder comprises a first filter unit and a second filter unit; a suction unit having a feeding tube for supplying soybeans; a lateral side of the suction unit being installed with a blower and a sound canceller so that soybean can enter into the suction unit; a feeding unit connected to the suction unit and the first filter unit; an electric controller serving to control the feeding unit; a regeneration barrel set connected to the first filter unit and the second filter unit for mixing and agitating soybean dregs from the first filter unit with water; and then the mixed dregs and water being fed into the second filter unit; a reuse barrel set connected to the first filter unit for feeding liquid from the second filter unit to the regeneration barrel set and then to the first filter unit through a pump.