Abstract: Organic-inorganic hybrid perovskites have attracted substantial attention because of their excellent physical properties, which enable them to serve as the active material in emerging hybrid solar cells. Here, we proposed a new type of thin-film field-effect transistor (TFT) with an organic-inorganic hybrid perovskite channel layer. The organic-inorganic hybrid perovskite material has advantages of a high mobility like that of an inorganic semiconductor and the easy process like an organic layer. A TFT using CH₃NH₃PbI₃ as the semiconducting channel was demonstrated. The effect of the evaporation amount of PbI₂ on the crystallization and thickness of CH₃NH₃PbI₃ films was studied. The organic-inorganic hybrid perovskite thin film with an average grain size of 1µm and a smooth surface has been achieved . The MoO3 was adopted as a buffer layer between metal electrodes and the active layer, which remarkably reduced the contact resistance from 705 kΩ·cm to 0.164 kΩ·cm, resulting in the improvement of the interface characteristics and performance of devices. The organic-inorganic hybrid perovskite TFT with the field effect mobility of 3.88cm²/V.s and the subthreshold slope of 1.6 V/dec. was achieved. Fig. 1 shows its transfer curves. This kind of TFT can be processed by cheap, low-temperature techniques, which suggest that it may be suitable for applications that require low cost, a large area, and the flexibility. Molecular engineering of the organic and inorganic components of the hybrids perovskite is expected to further improve device performance for high speed application.