The invention relates to a laser cutting device for a battery tab. The laser cutting device comprises a laser head, a feeding device, a cutting supporting plate and a waste material separating device,wherein the feeding device comprises a feeding roller and a discharging roller which are arranged at intervals; the cutting supporting plate is arranged between the feeding roller and the dischargingroller, and a first negative pressure port, a second negative pressure port and a third negative pressure port are sequentially arranged on the cutting supporting plate in the advancing direction ofa material belt; the laser head can cut the material belt passing through the second negative pressure port; and the waste material separating device can be used for separating waste material after being cut and separated from the material belt. According to the cutting device for the battery tab, the cutting supporting plate is sequentially provided with the first negative pressure port, the second negative pressure port and the third negative pressure port along the advancing direction of the material belt, so that the material belt enters the cutting supporting plate, the material belt canbe stably attached to the cutting supporting plate during cutting and after cutting, so that the material belt can be prevented from swinging and turning to affect cutting.