Interferon (IFN) was discovered in 1957 and was defined as an antiviral substance.However,people can not get enough IFN materials for research or clinical trial in more than 20 years after its discovery.Until 1979,IFN was cloned by Taniguchi in Japan and IFN-2a and IFN-2b was marked for the treatment of hepatitis B patients in 1986 in USA.IFN has been now become a good drug in the world with its sale volume to several billion USD.