The invention relates to the technical field of logistics equipment, in particular to a mechanical unstacking method and device for boxed drugs. The entire unstacking processes are that each layer of boxed drug stack is stacked up regularly, a layer splicing device can be used for enabling layer splitting processing to be conducted on the boxed drugs which are stacked in an entire tray mode, the topside layer is split and taken every time, transferring separation and consequent putting are conducted on each layer after splitting and taking, and single piece separation of the boxed drugs of the entire tray is achieved. The mechanical unstacking device comprises the layer splitting device, a transferring and separating device and a single piece separating device. According to the mechanical unstacking method and device for the boxed drugs, automatic unstacking of the boxed drugs can be achieved, the labor intensity for unstacking of an operator can be reduced, operation is stable, cost is low, and maintaining is convenient.