The invention discloses a peelable and biodegradable polyurethane protective film, a preparation method and application thereof. The protective film comprises the following raw materials by weight: 40-70 parts of thermoplastic polyurethane, 10-30 parts of biodegradable polyester, 0.01-0.5 part of a corrosion inhibitor, 1-10 parts of filler and 5-30 parts of a plasticizer. The preparation method comprises: 1) selecting materials according to the composition and weight part of each component prescribed in the formula; 2) putting the raw materials into a banbury mixer, performing stirring at 140-180DEG C for 5-15min till uniform mixing melting; 3) carrying out extrusion granulation and cooling to obtain an anti-bump and anti-corrosion protective film particle semi-finished product, during use, heating the semi-finished product to 160DEG C to melt it into liquid, then spraying the liquid on a metal component surface, and conducting cooling so as to form a 3-5micrometer protective film. The peelable and biodegradable polyurethane protective film provided by the invention has a simple formula and no pollution, and is especially suitable for temporary protection of metal raw materials and semi-finished products. The peelable and biodegradable polyurethane protective film is convenient to make and use, has no residual protective film after peeling, and can be biodegradable after abandonment.