The invention provides a preparation device and a preparation method of a large-area perovskite solar cell. The device sequentially comprises an FTO scribing P1 module, an electron transport layer coating module, an infrared radiation module, an electron transport layer cooling module, a perovskite precursor solution slit coating module, a perovskite wet film reduced pressure distillation module,a composite optical wave annealing module, a perovskite layer cooling module, a hole transport layer coating module, a hole layer blow-drying module, a mechanical scribing P2 module, an electrode evaporation module and a mechanical scribing P3 module, wherein the perovskite wet film reduced pressure distillation module comprises a cavity, a first transmission door, a second transmission door, a pneumatic piston and multiple groups of parallel booster pump devices; the first transmission door and the second transmission door are arranged on the two sides of the cavity respectively, and are usedfor an FTO glass carrier to pass through; the pneumatic piston is hermetically connected with the cavity; and the multiple groups of parallel booster pump devices communicate with the cavity. According to the preparation device and the preparation method, a wet film can be treated, and the large-scale production of the perovskite solar cell can be realized.