Tannic acid was used as the cross-linking agent, castor oil as the polyol of polyurethane, isophorone diisocyanate as the polyisocyanate of polyurethane, and bis(2-hydroxyethyl) disulfide and 1, 4-butanediol as the chain extender of polyurethane. Tannic acid-based polyurethanes were prepared by the pre-polymerization method, and the effects of the dosages of tannic acid and bis(2-hydroxyethyl) disulfide on the glass transition temperatures, thermal stability and self-repairing properties of polyurethanes were studied. self-repairing properties, while the biodegradation properties of tannic acid-based polyurethane films were evaluated using a lipase-based enzymatic degradation method. It was shown that an increase in the dosage of tannic acid led to an increase in the glass transition temperature of tannic acid-based polyurethane films and enhanced the thermal stability, while an increase in bis(2-hydroxyethyl)disulfide had no effect on the glass transition temperature of the films, but the thermal stability of the films was reduced; the self-healing efficiency of the STPU4 films was as high as 95% under the specific conditions (80 ℃, 3 h). In addition, the mass loss of the STPU4 membrane reached 68.3% after 140 h of lipolytic digestion.