A banknote stacking device, comprising: an input mechanism configured to convey banknotes one by one, which comprises an upper conveying belt and an upper conveying rotating shaft configured to drive the upper conveying belt; a stacking platform mechanism configured to stack and support banknotes conveyed by the input mechanism one by one, which comprises a platform configured to carry banknotes, wherein the platform and two baffles (22, 23) arranged front and rear in a banknote conveying direction define a space for stacking and storing banknotes, and the platform is controlled by a lifting mechanism to selectively move up and down; and a pressing and conveying mechanism located above the stacking platform mechanism and configured to press banknotes and convey the banknotes stacked on the platform forward, wherein the pressing and conveying mechanism has a pressing rod, and the pressing rod has one end rotatably arranged on the upper conveying rotating shaft and another end forming a free end and falling freely towards the platform, the rotatable securing end and the free end of the pressing rod are respectively provided with a first concave wheel and a second concave wheel, and a first O-shaped belt is arranged on the first concave wheel and the second concave wheel, wherein the first concave wheel rotates synchronously with the upper conveying rotating shaft, characterized in that, a belt conveying part is provided on the platform, and the belt conveying part comprises a flat belt and two flat belt pulleys configured to support and drive the flat belt, each of the flat belt pulleys is mounted onto the platform via a pulley rotating shaft, and the pulley rotating shaft is equipped with a connecting gear configured to receive external power, wherein an elastic strip is further provided on the platform, the elastic strip has two ends fixed onto the platform and a middle portion forming an arched elastic platform part, wherein the elastic platform part is higher than the flat belt by 1mm to 2mm in a free state. an input mechanism configured to convey banknotes one by one, which comprises an upper conveying belt and an upper conveying rotating shaft configured to drive the upper conveying belt; a stacking platform mechanism configured to stack and support banknotes conveyed by the input mechanism one by one, which comprises a platform configured to carry banknotes, wherein the platform and two baffles (22, 23) arranged front and rear in a banknote conveying direction define a space for stacking and storing banknotes, and the platform is controlled by a lifting mechanism to selectively move up and down; and a pressing and conveying mechanism located above the stacking platform mechanism and configured to press banknotes and convey the banknotes stacked on the platform forward, wherein the pressing and conveying mechanism has a pressing rod, and the pressing rod has one end rotatably arranged on the upper conveying rotating shaft and another end forming a free end and falling freely towards the platform, the rotatable securing end and the free end of the pressing rod are respectively provided with a first concave wheel and a second concave wheel, and a first O-shaped belt is arranged on the first concave wheel and the second concave wheel, wherein the first concave wheel rotates synchronously with the upper conveying rotating shaft, characterized in that, a belt conveying part is provided on the platform, and the belt conveying part comprises a flat belt and two flat belt pulleys configured to support and drive the flat belt, each of the flat belt pulleys is mounted onto the platform via a pulley rotating shaft, and the pulley rotating shaft is equipped with a connecting gear configured to receive external power, wherein an elastic strip is further provided on the platform, the elastic strip has two ends fixed onto the platform and a middle portion forming an arched elastic platform part, wherein the elastic platform part is higher than the flat belt by 1mm to 2mm in a free state.