Recently, the oxide semiconductor, which is possible to substitute for Si-based devices, has been studied for their advantages such as transparent, high carrier mobility and low cost. In many processes it was reported to make the oxide semiconductor. Besides, we tried the solution process for high productivity and used In₂O₃ to active layer of TFTs by sol-gel reaction. As a result, we obtained the advantages i.e. efficiency of the productivity, processing time and low cost. The performance of TFTs by solution process shows 0.02 cm2/Vs field effect mobility and 10⁶ I_on/I_off ratio.