The invention discloses a preparation method of an
alumina thin film in the field of a
thin film transistor. The preparation method comprises the following steps of: preparing
aluminium precursor solution, i.e., dissolving a precursor material containing
aluminium metal ions and a stabilizer in solution and sufficiently stirring to sufficiently dissolve the precursor material and the stabilizer to obtain the precursor solution; and preparing the
alumina thin film, i.e.,
coating the prepared reaction solution on a
coating surface to form a film and carrying out heat treatment program to obtain the
alumina thin film. The invention also relates to the alumina thin film prepared by the preparation method and application of the alumina thin film in the
transistor. The application comprises the
thin film transistor of the alumina thin film and a preparation method of the
thin film transistor. According to the preparation method of the alumina thin film, which is disclosed by the invention, by adding a right amount of stabilizer for stabilizing an alumina precursor material, a
metal organic complex is formed by the precursor material of
aluminium through the coordination
dissolution reaction; the complex can be well dissolved in the solution and has low
thermal decomposition temperature; and the heat treatment temperature in the preparing process is reduced.