The invention discloses a composite stent and a preparation method and application thereof. The composite stent is prepared from, by weight, 1-100 parts of collagen, 1-100 parts of nanocrystalline cellulose and 1-10 parts of modified superparamagnetism nanometer ferroferric oxide. The invention further discloses the preparation method of the composite stent. The porous composite stent prepared through the method is excellent in mechanical strength property, good in biocompatibility and good in degradation property, and a three-dimensional grid structure gap can provide an adhesion increment environment suitable for a host cell; meanwhile, superparamagnetism nanometer ferroferric oxide nano particles can well provide the mark imaging function and conduct nondestructive dynamic monitoring onthe morphology of new cartilage. Collagen is combined with nanocrystalline cellulose to simulate an environment model similar to a human body bone, a nutrient environment space needed by cell growthand reproduction during cartilage defect repair is replaced, and cartilage defects are repaired rapidly.