The invention relates to a preparation method of an environment-friendly spraying film material, and belongs to the technical field of preparation of spraying film materials. The preparation method comprises the following steps of firstly, mixing cassava starch and hydrochloric acid, heating, adding hydrogen peroxide for oxidation treatment, adding maleic anhydride to stir and react, and collecting, so as to obtain a mixture; stirring with polyethylene, glutaraldehyde and other matters, heating and reacting; utilizing a cobalt source radiation source to radiate and modify, collecting a discharged matter, filtering the discharged matter, washing and drying filter residues, and collecting a drying matter; finally, stirring the drying matter with silicon oil, vinyl tri-t-butoxide peroxide silane and other matters, and reacting, so as to obtain the environment-friendly spraying film material. The prepared environment-friendly spraying film material has the advantages that the bonding ability between the environment-friendly spraying film material and a substrate layer is stronger, and the stripping strength of the spraying film paper is increased to 0.7 to 0.9N/25mm; the spraying film material is degradable, and can be completely degraded within 7 to 9 months, and the green and environment-friendly requirements are met.