The present disclosure relates to a film formulation for oral administration, containing tadalafil free base and a method of preparing the same, and a film may be provided with maximized dispersion stability of tadalafil free base in the film by the addition of a dispersion stabilizing agent in small amounts without unique fragrance or favor that may appear when other dispersion stabilizing agents known in the art are used, and an extremely low likelihood that a reagglomeration phenomenon of tadalafil free base particles will occur, and an amount of bubbles generated may be significantly reduced during a production process.