The invention discloses a cooling device for numerical-control machine tool processing. The cooling device comprises a base, wherein a PLC controller is mounted on the front side surface of the base;and an oil tank is fixedly arranged at the upper side of the base. The cooling device for numerical-control machine tool processing is simple in structure; reflowed cooling oil is sprayed to the upperside surface of an oil tank through a feeding tube and a spraying tube, so that a heat dissipation area is increased; a fan is utilized for performing air-cooling on sprayed mists, so that follow-upcooling cycle is met; a baffle cover and a filter plate are arranged to prevent cooling oil from splashing, and cooling oil in the oil tank is stirred by a vane board, so that oil residues in the cooling oil are adhered on the inner side surface of the oil tank, and therefore, a cleaning and maintaining rate is reduced; the oil residues are separated through an upper cover and a baffle plate, sothat the whole cooling system is prevented from being blocked; and an acid restrainer is added by an adder, so that a too low pH value as cooling oil reacts with a workpiece during the cycle is restrained, and therefore, corrosion, on the whole system, of cooling oil deterioration is avoided, operations are simple, and use is convenient.