The present disclosure relates to perovskite thin film low-pressure chemical deposition equipment and a usage method thereof, and application of the usage method. The equipment comprises a main chamber, wherein two precursor heating plates and a substrate holddown groove are respectively arranged in the main chamber, the precursor heating plates are respectively provided with precursor containers, a plurality of groups of substrates on which a thin film is to be deposited are arranged on the substrate holddown groove, each group is provided with two substrates which are tightly attached back to back, and the surface of each of the two substrates on which a thin film is to be deposited faces towards one end of the main chamber; the left and right ends of the main chamber respectively communicate with carrier gas pipelines provided with carrier gas inlet mass flow control valves, the main chamber also communicates with a vacuum providing unit, and the main chamber is also provided with a main chamber heater for heating the substrates; and the carrier gas pipelines on the two ends respectively communicate with solvent evaporators. By adopting simultaneous introduction of the gas from the two ends of the main chamber and the substrate back-to-back configuration mode, the rate of preparing the perovskite thin film by the method is doubled as compared with the existing methods.