The invention provides a film-forming solution. The film-forming solution is characterized by comprising the following components: 5-30wt% of alcohol-soluble protein, 1-5wt% of nano TiO2 particles, 0.1-3wt% of gelatinizing agent, 0.05-3wt% of coagulant aid, 0.1-3wt% of plasticizer, and the balance of ethanol water of which the volume ratio is 45-65%. The invention also provides a method for preparing the film-forming solution. Furthermore, the invention also provides application of the film-forming solution as a food preservation film. According to the film-forming solution provided by the invention, not only are the edibility, the safety and the stability of the preservation film improved due to the alcohol-soluble protein, but also the preservation film is degradable and free of pollution to the environment. The nano TiO2 particles are contained, so that the film-forming solution has unique barrier property and mechanical property after a film is formed, and has an antibacterial effect. In addition, the preparation method of the film-forming solution provided by the invention is simple in process, and low in cost. The preservation film not only is good in moisture resistance, but also does not become tacky after being moistened, is degradable, green and environment-friendly, can well keep the quality of the food, and prolongs the shelf life after being formed on the food surface.