The present invention relates to a fluorene derivative or a pharmaceutically acceptable salt thereof, a preparation method therefor, and a pharmaceutical composition comprising the same as an effective ingredient for preventing or treating HCV-related disease. A fluorene derivative according to the present invention is identified to exhibit an antiviral performance against not only HCV, but also highly against HCV mutants, particularly double mutants and thus can be used in a pharmaceutical composition for prevention or treatment of HCV-caused liver disease, such as acute hepatitis C, chronic hepatitis C, liver cirrhosis, hepatocellular cancer, etc., particularly, liver disease caused by mutants of HCV. The derivative can be useful in a pharmaceutical composition for prevention or treatment of HCV-related liver disease by which the problem of resistant mutation against conventional therapeutic agents is solved.