The invention provides a TPU thin film capable of being used for certificate anti-fake protection and a preparation method thereof. The TPU thin film is prepared from a base material layer and a TPU layer arranged on the base material layer, and an laser holography anti-fake image is printed on the TPU layer; the TPU layer is prepared from the following raw materials of, in parts by mass, 15-30 parts of isocyanate, 15-30 parts of isothiocyanate, 80-120 parts of oligomer dihydric alcohol, 10-20 parts of chain extenders and 2-5 parts of catalysts. The TPU thin film is prepared by adopting the method that a polyurethane elastomer is generated through polymerization firstly, and subjected to blow molding to form the film with the material of the base material layer through a double-layer co-extrusion film blowing machine, finally the laser holography anti-fake image is printed on the TPU layer. The TPU thin film provided by the invention has higher light transmittance rate and refractive index, and the laser holography anti-fake image is bright and clear, and convenient to identify.