A quantum-dot thin film, a display backplate, and a manufacturing method of the display backplate are provided. The display backplate includes a light-emitting module and a quantum-dot module. The light-emitting module includes a light-emitting main body and a composite protective functional layer which are stacked. The quantum-dot module includes a quantum-dot layer disposed on the composite protective functional layer and a common protective functional layer disposed on the quantum-dot layer. A thickness of the composite protective functional layer is less than a thickness of the common protective functional layer.