The invention relates to the technical field of packaging materials, in particular to a biodegradable packaging material and a preparation method thereof. The biodegradable packaging material is prepared from starch, cellulose, chitin, protein, polyvinyl alcohol, a polymerizing agent, a plasticizer and a biodegradable additive; the material is prepared from the following components in parts by weight: 20-40 parts of starch, 15-25 parts of cellulose, 15-25 parts of chitin, 10-20 parts of protein, 2-6 parts of polyvinyl alcohol, 1-3 parts of a polymerizing agent, 2-4 parts of a plasticizer and 3-5 parts of a biodegradable additive. The material is good in hydrophobic capacity, oil resistance, water resistance and high temperature resistance, and has the excellent properties of proper strength, grease resistance, flexibility, transparency, odorlessness, odorlessness, easiness in degradation, and has the good film forming characteristic; The biodegradable packaging material is high in decomposition rate, can realize biodegradation, improves environmental protection, and has better biodegradation characteristics.