The invention discloses an automatic splitting-in-half device for livestock slaughtering. The device includes a transfer rod, wherein a plurality of connecting belts are fixedly disposed on the transfer rod, a hook is fixedly disposed on each connecting ring, a sliding block is movably disposed on a sliding rail, one end, far away from the sliding block, of a connecting rod is disposed on a cutting wheel, and one end, far away from a nut seat, of a push rod is fixed on the sliding block; and a driving gear is fixedly arranged on a screw rod in a penetrated mode, and the center of one side, faraway from the transfer rod, of a driven gear is fixedly provided with a cleaning tube. The invention provides the automatic splitting-in-half device for livestock slaughtering. The device can automatically perform splitting-in-half cutting on livestock in turn without manual assistance. During the splitting-in-half cutting, the device, on the one hand, can brush and clean livestock and prevent stain and grimy blood on the skin from affecting the cleanliness of the cutting surface and a cutting knife, and on the other hand, can stir a cleaning liquid. Besides, the above three functions are alldriven by the same rotating motor so as to save energy, to concentrate functions and to be worth promoting.