According to the report from World Health Organization (WHO), about two billion people worldwide have been infected with hepatitis B virus (HBV), of which 350 million people with chronic HBV infection. Now China has 130 million HBV carriers and 30 million patients suffered from hepatitis B. About 20%～40% of patients after years of inflammatory damage may develop into liver cirrhosis and liver cancer. Even today, however, people still have not found a specific drug that can completely cure chronic hepatitis B. Since the phenomenon of RNA interference (RNAi) was discovered, people have been constantly trying to apply it to the anti-viral drug research and development. Findings show that RNAi can indeed inhibit the replication of HBV. However, the efficiency of gene silencing varies considerably due to the different sequences of RNAi. In addition, the safety and effectiveness of RNAi-based antiviral drugs tested on humans still need to be further investigated. And the "off target" phenomenon of RNAi is another problem that must be resolved before its clinical trial.