The invention discloses a single-chuck destacking machine, which comprises a rack, wherein a travelling trolley is connected with the rack in a sliding way and is driven by a travelling power device; a lifting frame is connected with the travelling trolley in a sliding way; a lift and pull device is also arranged on the travelling trolley and is used for driving the lifting frame to lift; two clamping plates are horizontally arranged under the lifting frame opposite to each other; limiting grooves are horizontally formed at the bottom of the lifting frame; sliding plates which are connected with the interior of the limiting groove in a sliding way are respectively and fixedly arranged at the tops of the two clamping plates; clamping blocks are respectively and fixedly arranged at the bottoms of the two clamping plates; and a clamping drive device which drives the clamping plates to move in an opposite direction is connected between the tops of the two clamping plates. The single-chuck destacking machine is simple in structure, and can automatically unload brick stacks, and manual brick unloading is not required; therefore, the labor efficiency of workers is high, and the labor intensity is low.