Hepatitis C virus (HCV) is one of hepatitis viruses,transmits mainly through blood and one of the major reasons to cause chronic hepatitis,liver cirrhosis and liver cancer.HCV infection is spontaneously resolved in about 30％ of acutely infected individuals.In those who develop chronic hepatitis,HCV therapy permanently eradicates infection in about 40 ％ of case after using antiviral therapy.At present,a combined therapy of pegylated interferon-α (PEG-IFN-α) and ribavirin (RBV) is recommended as standard of care for patients with chronic HCV infection.Recent studies have suggested that not only the patients who had been infected with different virus genotypes show different sensitivity to treatment,but also the patients from different ethnic backgrounds and even different individuals show quite difference in response to interferon therapy.Therefore,it is believed that both the viral and host' s genetic backgrounds would affect the antiviral therapy.This review describes the factors of both genetic background of human populations and different HCV genotypes that affect the outcome of anti-HCV treatment.