The invention discloses an antitumor medicine, an antitumor medicine for external application and a preparation method thereof. The raw materials of the antineoplastic drug include ‑OH, ‑COOH, ‑NH 2 A protein anti-tumor biomaterial of at least one group, a photocoupling agent and a solvent; the photocoupling agent includes an aromatic azide compound; , photocoupling agent and solvent mixed reaction in the system. Among them, the photocoupling agent aromatic azide compound is used as a modifier to modify the above protein anti-tumor biological materials, which has low cost, good modification effect, high yield and wide application range; the synthesized anti-tumor drug contains azidophenyl, With photosensitive activity, it can be photochemically fixed on the medical dressing to form an anti-tumor topical drug. The drug is tightly connected and not easy to fall off. It can continuously send death-inducing signals to tumor cells, prolong the action time of the drug, and improve the therapeutic effect.