According to the present invention, an ultra-fast method for preparing an organic/inorganic thin film by using self-diffusion effects comprises the steps of: forming a solution by dissolving one or more organic/inorganic materials in a solvent; forming an organic/inorganic thin film by supplying the formed solution onto a liquid substrate; and transferring the formed thin film to a substrate, wherein the step of forming an organic/inorganic thin film forms a thin film on the liquid substrate from the organic/inorganic materials through the occurrence of a self-diffusion phenomenon caused by a difference in surface tension between the liquid substrate and the solution, and through the occurrence of the evaporation of the solvent and the dissolution process of the solvent to the liquid substrate.