Disclosed a nuclease-resistant RNA aptamer for inhibiting the replication of HCV replicon. This aptamer is capable of binding specifically to HCV NS5B and inhibiting the proliferation of the HCV replicon, and is composed of at least one sequence selected from a group consisting of SEQ ID NOS. 1 to 4, in which a fluoro group is substituted for 2'-hydroxy of both U (uracil) and C (cytosine) bases, and SEQ ID NO. 4, which is tagged with a cholesteryl group at a 5' end and with idT at a 3' end. The RNA aptamer is useful in the diagnosis and treatment of HCV infection.