Hemagglutinin(HA)which is essential for influenza viral infection and replication has become a target for the design of anti-influenza drugs.A novel series of oligothiophene compounds focused on the target were synthesized as specific inhibitors against the H5 subtype of influenza A viruses because oligothiophene has stronger π–π interactions with residues F1102 and M241 of HA2 side chains.