Abstract: Cathepsin K (Cat K) is a cysteine protease expressed in osteoclasts, which is the key enzyme of bone resorption in the process of bone rebuilding. Related research confirms that inhibiting its activity is a new way for the treatment of osteoporosis. As the latest research and development of cathepsin K inhibitor, Odanacatib (ODN) can effectively inhibit bone absorption without inhibiting bone formation, and it also shows well tolerance and no obvious drug related adverse reaction, which provides a new option for treatment of osteoporosis.