The invention discloses a chemical and physical double-cross-linking high-strength chitin gel material and a preparation method thereof. The preparation method comprises the following steps: adding a cross-linking agent for partial chemical cross-linking at the gelatinization temperature lower than that of a chitin solution, subsequently soaking the chitin gel which is subjected to partial chemical cross-linking into a non-solvent for physical cross-linking, and washing with water, thereby obtaining double-cross-linking chitin hydrogel; replacing water in the double-cross-linking chitin hydrogel by an organic liquid, thereby obtaining chitin organic gel, and drying the double-cross-linking chitin hydrogel or the organic gel, thereby obtaining double-cross-linking chitin aerogel; and hot-rolling the double-cross-linking chitin hydrogel or the double-cross-linking chitin aerogel, thereby preparing double-cross-linking chitin biological plastic. The double-cross-linking chitin gel material disclosed by the invention is excellent in mechanical property, low density and high specific surface area, can be easily processed into finished products such as fiber, sheets, granules, films and columns, and is applicable to large-scale popularization and application.