A banknote stacking device, comprising: a piece-by-piece banknote conveying mechanism configured to convey a single sheet of banknote; an upper conveyor belt configured to provide a driving force to the banknote and arranged around a driving wheel, driven wheels (150, 154, 155) and a pinch roller which are arranged in a conveying direction of the banknote; an arc-shaped stacking plate, comprising three sections, a section near the piece-by-piece banknote conveying mechanism forms a rear arc-shaped plate, a section near the discharging outlet foms a front arc-shaped plate and a middle section forms a direction reversing device, configured to support the banknote, wherein the upper conveyor belt fitting closely to an arc-shaped surface of the arc-shaped stacking plate to define a conveying passage for the banknote, a length of the conveying passage is at least greater than a length of one sheet of the banknote in the conveying direction, and one end of the conveying passage abuts the piece-by-piece banknote conveying mechanism and is slightly lower than a delivering outlet of the conveying mechanism, and another end of the conveying passage forms a discharging port for a whole stack of banknotes; a movable blocking mechanism arranged on a section of the conveying passage close to the discharging port and configured to selectively block the banknote; a sensor device arranged at a tail end of the delivering outlet of the piece-by-piece banknote conveying mechanism and configured to detect the arrival and passing of a sheet of the banknote; and a control unit configured to control the upper conveyor belt to move or stop moving according to information feedback from the sensor device; wherein, an elastic sheet is arranged on the arc-shaped stacking plate at a position for stacking banknote, an end of the elastic sheet is fixed on the arc-shaped stacking plate, and a free end of the elastic sheet extends in a direction opposite to the conveying direction of the banknotes, the extending segment of the elastic sheet forms an arch and is configured to elastically support the upper conveyor belt, and a through-groove is provided in the front arc-shaped stacking plate at a position corresponding to the elastic sheet, and the free end of the elastic sheet is configured to extend and retract freely in the through-groove. a piece-by-piece banknote conveying mechanism configured to convey a single sheet of banknote; an upper conveyor belt configured to provide a driving force to the banknote and arranged around a driving wheel, driven wheels (150, 154, 155) and a pinch roller which are arranged in a conveying direction of the banknote; an arc-shaped stacking plate, comprising three sections, a section near the piece-by-piece banknote conveying mechanism forms a rear arc-shaped plate, a section near the discharging outlet foms a front arc-shaped plate and a middle section forms a direction reversing device, configured to support the banknote, wherein the upper conveyor belt fitting closely to an arc-shaped surface of the arc-shaped stacking plate to define a conveying passage for the banknote, a length of the conveying passage is at least greater than a length of one sheet of the banknote in the conveying direction, and one end of the conveying passage abuts the piece-by-piece banknote conveying mechanism and is slightly lower than a delivering outlet of the conveying mechanism, and another end of the conveying passage forms a discharging port for a whole stack of banknotes; a movable blocking mechanism arranged on a section of the conveying passage close to the discharging port and configured to selectively block the banknote; a sensor device arranged at a tail end of the delivering outlet of the piece-by-piece banknote conveying mechanism and configured to detect the arrival and passing of a sheet of the banknote; and a control unit configured to control the upper conveyor belt to move or stop moving according to information feedback from the sensor device; wherein, an elastic sheet is arranged on the arc-shaped stacking plate at a position for stacking banknote, an end of the elastic sheet is fixed on the arc-shaped stacking plate, and a free end of the elastic sheet extends in a direction opposite to the conveying direction of the banknotes, the extending segment of the elastic sheet forms an arch and is configured to elastically support the upper conveyor belt, and a through-groove is provided in the front arc-shaped stacking plate at a position corresponding to the elastic sheet, and the free end of the elastic sheet is configured to extend and retract freely in the through-groove.