H5N1 virus, one subtype of highly pathogenic influenza A virus in human infection, has recently received attention due to its unpredictable and high mortality. In this study, a series of arylsulfonamide derivatives were identified as improved H5N1 inhibitors for the influenza treatment by systematic structure-activity relationship investigation. Among them, the most potent H5N1 inhibitor 3h exhibited excellent antiviral activity against H5N1 virus with EC50 value of 0.006 μM and selectivity index 33543.3. Moreover, the molecular docking of 3h with M2 proton channel protein provides practical way for understanding the inhibition of H5N1 with this kind of compounds.