The invention relates to a medical dressing, and particularly discloses a polyurethane sponge dressing with anti-adhesion and hemostasis functions and a preparation method thereof. Biodegradable biological polyurethane sponge with good biocompatibility, mechanical properties and blood compatibility is selected and used, vaseline is smeared and dissolved on the surface, nanometer chitosan particle paraffin oil is added, and after smearing treatment, the polyurethane sponge dressing with anti-adhesion and hemostasis functions is obtained. The prepared sponge dressing has the pharmacological action of chitosan, has the effects of achieving antisepsis, moisture preservation and hemostasis, promoting wound healing and reducing scar formation, has no irritation to wound surfaces and is beneficial to prompting wound healing.