Abstract: "Innocent Owner Defense" has developed gradually from weak to strong in American law. It is now used for the protection of property of an innocent third party, which has brought new strength to American legal system. With a thorough analysis on its concept and applications, the study on this defense from the historical perspective not only means an in-depth knowledge of American civil forfeiture law, but also helps lay a solid foundation for the similar protection of property of an innocent third party in China.