The invention provides a method for preparing a zinc oxide thin-film transistor by a sol-gel method; the method comprises the following steps: firstly, an isopropyl alcohol solution containing zinc acetate and diethanolamine is prepared and coated on an ATO layer of ATO/ITO/glass matrix in a spin coating or tensioned membrane manner, wherein, the thicknesses of the ATO layer and an ITO layer are respectively below 400nm; preheating is carried out for 10 minutes to 15 minutes at the temperature from 150 DEG C to 2000 DEG C and then heat treatment is carried out for 15 minutes to 20 minutes at the temperature from 400 DEG C to 650 DEG C; the operations of coating, preheating and heat treatment are repeated till the thickness of a formed zinc oxide thin film reaches 30nm to 100nm; and an evaporation method is used for preparing source-drain electrode arrays on the surface of the zinc oxide thin film. The zinc oxide thin-film field-effect transistor that is prepared by adopting the methodhas a zinc oxide conductor thin film with ideal crystal structure and conductor performance, and overcomes the defects of high production cost in methods other than solution methods, and poor performance of zinc oxide thin-film field-effect transistors prepared by other solution methods.