HCV is a global public health issue with millions people affected around the world. Chronic HCV infection can lead to severe long-term consequences like cirrhosis, liver cancer and liver failure. The treatment of choice before 2011 was PEG-Interferon with low effectiveness and many unwanted side effects. The approval of direct-acting antiviral therapy in 2011 has significantly changed the treatment effectiveness of chronic HCV infection. This thesis aims to provide a overview the molecular basis of Direct-acting Antiviral, the pharmacology of each group of the Direct-acting antiviral agents including their clinical applications, as well as the challenges they are facing.