The invention discloses a preparation method of a perovskite light-emitting diode based on a spraying process. The method includes the steps: preparing a substrate of a base plate, sequentially preparing a positive-electrode layer, a hole transporting layer, a perovskite light-emitting layer, an electron transporting layer and a negative-electrode layer on the substrate; packaging the acquired base plate to complete preparation of a device. A preparation method of the perovskite light-emitting layer includes the steps: placing the base plate on a low-temperature plate to perform cooling; spraying perovskite material solution on the hole transporting layer by a spraying method once to obtain the perovskite light-emitting layer; directly placing the low-temperature base plate on a hot tableto anneal to complete preparation of the perovskite light-emitting layer. A perovskite light-emitting layer film is prepared by a low-temperature one-time spraying method, roughness is low, crystallinity is good, crystal particles are small, and brightness and quantum efficiency of the light-emitting diode can be improved.